# VNC and VNC-GW

This chapter describes how to use VNC services, including NVA and VNC-GW functions. Background information on NVAs, NVE s, UN s, and VN is available from the IETF. VNC-GW s support the import/export of routing information between VNC and CE routers operating within a VN. Both IP/Layer 3 (L3) VNs, and IP with Ethernet/Layer 2 (L2) VNs are supported.

BGP, with IP VPNs and Tunnel Encapsulation, is used to distribute VN information between NVAs. BGP based IP VPN support is defined in RFC 4364, and RFC 4659. Encapsulation information is provided via the Tunnel Encapsulation Attribute, RFC 5512.

The protocol that is used to communicate routing and Ethernet / Layer 2 (L2) forwarding information between NVAs and NVEs is referred to as the Remote Forwarder Protocol (RFP). OpenFlow is an example RFP. Specific RFP implementations may choose to implement either a hard-state or soft-state prefix and address registration model. To support a soft-state refresh model, a lifetime in seconds is associated with all registrations and responses.

The chapter also provides sample configurations for basic example scenarios.

## Configuring VNC

Virtual Network Control (VNC) service configuration commands appear in the router bgp section of the BGPD configuration file (Miscellaneous Configuration Examples). The commands are broken down into the following areas:

- General VNC configuration applies to general VNC operation and is primarily used to control the method used to advertise tunnel information.

- Remote Forwarder Protocol (RFP) configuration relates to the protocol used between NVAs and NVEs.

- VNC Defaults provides default parameters for registered NVEs.

- VNC NVE Group provides for configuration of a specific set of registered NVEs and overrides default parameters.

- Redistribution and Export control VNC-GW operation, i.e., the import/export of routing information between VNC and customer edge routers (CE s) operating within a VN.

### General VNC Configuration

### RFP Related Configuration

The protocol that is used to communicate routing and Ethernet / L2 forwarding information between NVAs and NVEs is referred to as the Remote Forwarder Protocol (RFP). Currently, only a simple example RFP is included in FRR. Developers may use this example as a starting point to integrate FRR with an RFP of their choosing, e.g., OpenFlow. The example code includes the following sample configuration:

rfp example-config-value VALUE

This is a simple example configuration parameter included as part of the RFP example code. VALUE must be in the range of 0 to 4294967295.

### VNC Defaults Configuration

The VNC Defaults section allows the user to specify default values for configuration parameters for all registered NVEs. Default values are overridden by VNC NVE Group Configuration.

vnc defaults

Enter VNC configuration mode for specifying VNC default behaviors. Use exit-vnc to leave VNC configuration mode. vnc defaults is optional.

    vnc defaults
    ... various VNC defaults
    exit-vnc

These are the statements that can appear between `vnc defaults` and `exit-vnc`. Documentation for these statements is given in VNC NVE Group Configuration.

- `rt import RT-LIST`

- `rt export RT-LIST`

- `rt both RT-LIST`

- `rd ROUTE-DISTINGUISHER`

- `l2rd NVE-ID-VALUE`

- `response-lifetime LIFETIME|infinite`

- `export bgp|zebra route-map MAP-NAME`

- `export bgp|zebra no route-map`

exit-vnc

  Exit VNC configuration mode.

### VNC NVE Group Configuration

A NVE Group corresponds to a specific set of NVEs. A Client NVE is assigned to an NVE Group based on whether there is a match for either its virtual or underlay network address against the VN and/or UN address prefixes specified in the NVE Group definition. When an NVE Group definition specifies both VN and UN address prefixes, then an NVE must match both prefixes in order to be assigned to the NVE Group. In the event that multiple NVE Groups match based on VN and/or UN addresses, the NVE is assigned to the first NVE Group listed in the configuration. If an NVE is not assigned to an NVE Group, its messages will be ignored.

Configuration values specified for an NVE group apply to all member NVEs and override configuration values specified in the VNC Defaults section.

At least one `nve-group` is mandatory for useful VNC operation.

vnc nve-group NAME

  Enter VNC configuration mode for defining the NVE group name. Use exit or exit-vnc to exit group configuration mode.

      vnc nve-group group1
      ... configuration commands
      exit-vnc

The following statements are valid in an NVE group definition:

l2rd NVE-ID-VALUE

  Set the value used to distinguish NVEs connected to the same physical Ethernet segment (i.e., at the same location) [1].

  The nve-id subfield may be specified as either a literal value in the range 1-255, or it may be specified as auto:vn, which means to use the least-significant octet of the originating NVE's VN address.

prefix vn|un A.B.C.D/M|X:X::X:X/M

  Specify the matching prefix for this NVE group by either virtual-network address (vn) or underlay-network address (un). Either or both virtual-network and underlay-network prefixes may be specified. Subsequent virtual-network or underlay-network values within a vnc nve-group exit-vnc block override their respective previous values.

  These prefixes are used only for determining assignments of NVEs to NVE Groups.

rd ROUTE-DISTINGUISHER

  Specify the route distinguisher for routes advertised via BGP VPNs. The route distinguisher must be in one of these forms:

  - `IPv4-address:two-byte-integer`

  - `four-byte-autonomous-system-number:two-byte-integer`

  - `two-byte-autonomous-system-number:four-byte-integer`

  - `auto:vn:two-byte-integer`

  Routes originated by NVEs in the NVE group will use the group's specified route-distinguisher when they are advertised via BGP. If the auto form is specified, it means that a matching NVE has its RD set to `rd_type=IP=1:IPv4-address=VN-address:two-byte-integer`, for IPv4 VN addresses and `rd_type=IP=1:IPv4-address=Last-four-bytes-of-VN-address:two-byte-integer`, for IPv6 VN addresses.

  If the NVE group definition does not specify a route-distinguisher, then the default route-distinguisher is used. If neither a group nor a default route-distinguisher is configured, then the advertised RD is set to `two-byte-autonomous-system-number=0:four-byte-integer=0`.

response-lifetime LIFETIME|infinite

  Specify the response lifetime, in seconds, to be included in RFP response messages sent to NVEs. If the value 'infinite' is given, an infinite lifetime will be used.

  Note that this parameter is not the same as the lifetime supplied by NVEs in RFP registration messages. This parameter does not affect the lifetime value attached to routes sent by this server via BGP.

  If the NVE group definition does not specify a response-lifetime, the default response-lifetime will be used. If neither a group nor a default response-lifetime is configured, the value 3600 will be used. The maximum response lifetime is 2147483647.

rt export RT-LIST

rt import RT-LIST

rt both RT-LIST

  Specify route target import and export lists. rt-list is a space-separated list of route targets, each element of which is in one of the following forms:

  - `IPv4-address:two-byte-integer`

  - `four-byte-autonomous-system-number:two-byte-integer`

  - `two-byte-autonomous-system-number:four-byte-integer`

  The first form, rt export, specifies an export rt-list. The export rt-list will be attached to routes originated by NVEs in the NVE group when they are advertised via BGP. If the NVE group definition does not specify an export rt-list, then the default export rt-list is used. If neither a group nor a default export rt-list is configured, then no RT list will be sent; in turn, these routes will probably not be processed by receiving NVAs.

  The second form, rt import specifies an import rt-list, which is a filter for incoming routes. In order to be made available to NVEs in the group, incoming BGP VPN routes must have RT lists that have at least one route target in common with the group's import rt-list.

  If the NVE group definition does not specify an import filter, then the default import rt-list is used. If neither a group nor a default import rt-list is configured, there can be no RT intersections when receiving BGP routes and therefore no incoming BGP routes will be processed for the group.

  The third, rt both, is a shorthand way of specifying both lists simultaneously, and is equivalent to rt export `rt-list` followed by rt import `rt-list`.

export bgp|zebra route-map MAP-NAME

  Specify that the named route-map should be applied to routes being exported to bgp or zebra. This parameter is used in conjunction with Configuring Export of Routes to Other Routing Protocols. This item is optional.

export bgp|zebra no route-map

  Specify that no route-map should be applied to routes being exported to bgp or zebra. This parameter is used in conjunction with Configuring Export of Routes to Other Routing Protocols. This item is optional.

export bgp|zebra ipv4|ipv6 prefix-list LIST-NAME

  Specify that the named prefix-list filter should be applied to routes being exported to bgp or zebra. Prefix-lists for ipv4 and ipv6 are independent of each other. This parameter is used in conjunction with Configuring Export of Routes to Other Routing Protocols. This item is optional.

export bgp|zebra no ipv4|ipv6 prefix-list

  Specify that no prefix-list filter should be applied to routes being exported to bgp or zebra. This parameter is used in conjunction with Configuring Export of Routes to Other Routing Protocols. This item is optional.

### VNC L2 Group Configuration

The route targets advertised with prefixes and addresses registered by an NVE are determined based on the NVE's associated VNC NVE Group Configuration, VNC NVE Group Configuration. Layer 2 (L2) Groups are used to override the route targets for an NVE's Ethernet registrations based on the Logical Network Identifier and label value. A Logical Network Identifier is used to uniquely identify a logical Ethernet segment and is conceptually similar to the Ethernet Segment Identifier defined in RFC 7432. Both the Logical Network Identifier and Label are passed to VNC via RFP prefix and address registration.

Note that a corresponding NVE group configuration must be present, and that other NVE associated configuration information, notably RD, is not impacted by L2 Group Configuration.

vnc l2-group NAME

  Enter VNC configuration mode for defining the L2 group name. Use exit or exit-vnc to exit group configuration mode.

      vnc l2-group group1
        ... configuration commands
      exit-vnc

  Delete the L2 group named name.

The following statements are valid in a L2 group definition:

logical-network-id VALUE

  Define the Logical Network Identifier with a value in the range of 0-4294967295 that identifies the logical Ethernet segment.

labels LABEL-LIST

  Add or remove labels associated with the group. label-list is a space separated list of label values in the range of 0-1048575.

rt import RT-TARGET

rt export RT-TARGET

rt both RT-TARGET

  Specify the route target import and export value associated with the group. A complete definition of these parameters is given above, VNC NVE Group Configuration.

### Configuring Redistribution of Routes from Other Routing Protocols

Routes from other protocols (including BGP) can be provided to VNC (both for RFP and for redistribution via BGP) from three sources: the zebra kernel routing process; directly from the main (default) unicast BGP RIB; or directly from a designated BGP unicast exterior routing RIB instance.

The protocol named in the vnc redistribute command indicates the route source: bgp-direct routes come directly from the main (default) unicast BGP RIB and are available for RFP and are redistributed via BGP; bgp-direct-to-nve-groups routes come directly from a designated BGP unicast routing RIB and are made available only to RFP; and routes from other protocols come from the zebra kernel routing process. Note that the zebra process does not need to be active if only bgp-direct or bgp-direct-to-nve-groups routes are used.

#### zebra routes

Routes originating from protocols other than BGP must be obtained via the zebra routing process. Redistribution of these routes into VNC does not support policy mechanisms such as prefix-lists or route-maps.

#### bgp-direct routes

bgp-direct redistribution supports policy via prefix lists and route-maps. This policy is applied to incoming original unicast routes before the redistribution translations (described below) are performed.

Redistribution of bgp-direct routes is performed in one of three possible modes: plain, nve-group, or resolve-nve. The default mode is plain. These modes indicate the kind of translations applied to routes before they are added to the VNC RIB.

In plain mode, the route's next hop is unchanged and the RD is set based on the next hop. For bgp-direct redistribution, the following translations are performed:

- The VN address is set to the original unicast route's next hop address.

- The UN address is NOT set. (VN->UN mapping will occur via ENCAP route or attribute, based on vnc advertise-un-method setting, generated by the RFP registration of the actual NVE)

- The RD is set to as if auto:vn:0 were specified (i.e., rd_type=IP=1:IPv4-address=VN-address:two-byte-integer=0)

- The RT list is included in the extended community list copied from the original unicast route (i.e., it must be set in the original unicast route).

In nve-group mode, routes are registered with VNC as if they came from an NVE in the nve-group designated in the vnc redistribute nve-group command. The following translations are performed:

- The next hop/VN address is set to the VN prefix configured for the redistribute nve-group.

- The UN address is set to the UN prefix configured for the redistribute nve-group.

- The RD is set to the RD configured for the redistribute nve-group.

- The RT list is set to the RT list configured for the redistribute nve-group. If bgp-direct routes are being redistributed, any extended communities present in the original unicast route will also be included.

In resolve-nve mode, the next hop of the original BGP route is typically the address of an NVE connected router (CE) connected by one or more NVEs. Each of the connected NVEs will register, via RFP, a VNC host route to the CE. This mode may be though of as a mechanism to proxy RFP registrations of BGP unicast routes on behalf of registering NVEs.

Multiple copies of the BGP route, one per matching NVE host route, will be added to VNC. In other words, for a given BGP unicast route, each instance of a RFP-registered host route to the unicast route's next hop will result in an instance of an imported VNC route. Each such imported VNC route will have a prefix equal to the original BGP unicast route's prefix, and a next hop equal to the next hop of the matching RFP-registered host route. If there is no RFP-registered host route to the next hop of the BGP unicast route, no corresponding VNC route will be imported.

The following translations are applied:

- The Next Hop is set to the next hop of the NVE route (i.e., the VN address of the NVE).

- The extended community list in the new route is set to the union of:

- Any extended communities in the original BGP route

  - Any extended communities in the NVE route

  - An added route-origin extended community with the next hop of the original BGP route is added to the new route. The value of the local administrator field defaults 5226 but may be configured by the user via the roo-ec-local-admin parameter.

- The Tunnel Encapsulation attribute is set to the value of the Tunnel Encapsulation attribute of the NVE route, if any.

#### bgp-direct-to-nve-groups routes

Unicast routes from the main or a designated instance of BGP may be redistributed to VNC as bgp-direct-to-nve-groups routes. These routes are NOT announced via BGP, but they are made available for local RFP lookup in response to queries from NVEs.

A non-main/default BGP instance is configured using the router bgp AS view NAME command as described elsewhere in this document.

In order for a route in the unicast BGP RIB to be made available to a querying NVE, there must already be, available to that NVE, an (interior) VNC route matching the next hop address of the unicast route. When the unicast route is provided to the NVE, its next hop is replaced by the next hop of the corresponding NVE. If there are multiple longest-prefix-match VNC routes, the unicast route will be replicated for each.

There is currently no policy (prefix-list or route-map) support for bgp-direct-to-nve-groups routes.

#### Redistribution Command Syntax

vnc redistribute ipv4|ipv6 bgp|bgp-direct|ipv6 bgp-direct-to-nve-groups|connected|kernel|ospf|rip|static

vnc redistribute ipv4|ipv6 bgp-direct-to-nve-groups view VIEWNAME

  Import (or do not import) prefixes from another routing protocols. Specify both the address family to import (ipv4 or ipv6) and the protocol (bgp, bgp-direct, bgp-direct-to-nve-groups, connected, kernel, ospf, rip, or static). Repeat this statement as needed for each combination of address family and routing protocol. Prefixes from protocol bgp-direct are imported from unicast BGP in the same bgpd process. Prefixes from all other protocols (including bgp) are imported via the zebra kernel routing process.

vnc redistribute mode plain|nve-group|resolve-nve

  Redistribute routes from other protocols into VNC using the specified mode. Not all combinations of modes and protocols are supported.

vnc redistribute nve-group GROUP-NAME

  When using nve-group mode, assign (or do not assign) the NVE group group-name to routes redistributed from another routing protocol. group-name must be configured using vnc nve-group.

  The VN and UN prefixes of the nve-group must both be configured, and each prefix must be specified as a full-length (/32 for IPv4, /128 for IPv6) prefix.

vnc redistribute lifetime LIFETIME|infinite

  Assign a registration lifetime, either lifetime seconds or infinite, to prefixes redistributed from other routing protocols as if they had been received via RFP registration messages from an NVE. lifetime can be any integer between 1 and 4294967295, inclusive.

vnc redistribute resolve-nve roo-ec-local-admin 0-65536

  Assign a value to the local-administrator subfield used in the Route Origin extended community that is assigned to routes exported under the resolve-nve mode. The default value is 5226.

The following four prefix-list and route-map commands may be specified in the context of an nve-group or not. If they are specified in the context of an nve-group, they apply only if the redistribution mode is nve-group, and then only for routes being redistributed from bgp-direct. If they are specified outside the context of an nve-group, then they apply only for redistribution modes plain and resolve-nve, and then only for routes being redistributed from bgp-direct.

vnc redistribute bgp-direct (ipv4|ipv6) prefix-list LIST-NAME

  When redistributing bgp-direct routes, specifies that the named prefix-list should be applied.

vnc redistribute bgp-direct no (ipv4|ipv6) prefix-list

  When redistributing bgp-direct routes, specifies that no prefix-list should be applied.

vnc redistribute bgp-direct route-map MAP-NAME

  When redistributing bgp-direct routes, specifies that the named route-map should be applied.

vnc redistribute bgp-direct no route-map

  When redistributing bgp-direct routes, specifies that no route-map should be applied.

### Configuring Export of Routes to Other Routing Protocols

Routes from VNC (both for RFP and for redistribution via BGP) can be provided to other protocols, either via zebra or directly to BGP.

It is important to note that when exporting routes to other protocols, the downstream protocol must also be configured to import the routes. For example, when VNC routes are exported to unicast BGP, the BGP configuration must include a corresponding redistribute vnc-direct statement.

export bgp|zebra mode none|group-nve|registering-nve|ce

  Specify how routes should be exported to bgp or zebra. If the mode is none, routes are not exported. If the mode is group-nve, routes are exported according to nve-group or vrf-policy group configuration (VNC NVE Group Configuration): if a group is configured to allow export, then each prefix visible to the group is exported with next hops set to the currently-registered NVEs. If the mode is registering-nve, then all VNC routes are exported with their original next hops. If the mode is ce, only VNC routes that have an NVE connected CE Router encoded in a Route Origin Extended Community are exported. This extended community must have an administrative value that matches the configured roo-ec-local-admin value. The next hop of the exported route is set to the encoded NVE connected CE Router.

  The default for both bgp and zebra is mode none.

vnc export bgp|zebra group-nve group GROUP-NAME

vnc export bgp|zebra group-nve no group GROUP-NAME

  When export mode is group-nve, export (or do not export) prefixes from the specified nve-group or vrf-policy group to unicast BGP or to zebra. Repeat this statement as needed for each nve-group to be exported. Each VNC prefix that is exported will result in N exported routes to the prefix, each with a next hop corresponding to one of the N NVEs currently associated with the nve-group.

Some commands have a special meaning under certain export modes.

`export bgp|zebra ipv4|ipv6 prefix-list LIST-NAME`

  When export mode is ce or registering-nve, specifies that the named prefix-list should be applied to routes being exported to bgp or zebra. Prefix-lists for ipv4 and ipv6 are independent of each other.

`export bgp|zebra no ipv4|ipv6 prefix-list`

  When export mode is ce or registering-nve, specifies that no prefix-list should be applied to routes being exported to bgp or zebra.

`export bgp|zebra route-map MAP-NAME`

  When export mode is ce or registering-nve, specifies that the named route-map should be applied to routes being exported to bgp or zebra.

`export bgp|zebra no route-map`

  When export mode is ce or registering-nve, specifies that no route-map should be applied to routes being exported to bgp or zebra.

  When the export mode is group-nve, policy for exported routes is specified per-NVE-group or vrf-policy group inside a nve-group RFG-NAME block via the following commands(VNC NVE Group Configuration):

`export bgp|zebra route-map MAP-NAME`

  This command is valid inside a nve-group RFG-NAME block. It specifies that the named route-map should be applied to routes being exported to bgp or zebra.

`export bgp|zebra no route-map`

  This command is valid inside a nve-group RFG-NAME block. It specifies that no route-map should be applied to routes being exported to bgp or zebra.

`export bgp|zebra ipv4|ipv6 prefix-list LIST-NAME`

  This command is valid inside a nve-group RFG-NAME block. It specifies that the named prefix-list filter should be applied to routes being exported to bgp or zebra. Prefix-lists for ipv4 and ipv6 are independent of each other.

`export bgp|zebra no ipv4|ipv6 prefix-list`

  This command is valid inside a nve-group RFG-NAME block. It specifies that no prefix-list filter should be applied to routes being exported to bgp or zebra.

## Manual Address Control

The commands in this section can be used to augment normal dynamic VNC. The add vnc commands can be used to manually add IP prefix or Ethernet MAC address forwarding information. The clear vnc commands can be used to remove manually and dynamically added information.

add vnc prefix (A.B.C.D/M|X:X::X:X/M) vn (A.B.C.D|X:X::X:X) un (A.B.C.D|X:X::X:X) [cost (0-255)] [lifetime (infinite|(1-4294967295))] [local-next-hop (A.B.C.D|X:X::X:X) [local-cost (0-255)]]

  Register an IP prefix on behalf of the NVE identified by the VN and UN addresses. The cost parameter provides the administrative preference of the forwarding information for remote advertisement. If omitted, it defaults to 255 (lowest preference). The lifetime parameter identifies the period, in seconds, that the information remains valid. If omitted, it defaults to infinite. The optional local-next-hop parameter is used to configure a nexthop to be used by an NVE to reach the prefix via a locally connected CE router. This information remains local to the NVA, i.e., not passed to other NVAs, and is only passed to registered NVEs. When specified, it is also possible to provide a local-cost parameter to provide a forwarding preference. If omitted, it defaults to 255 (lowest preference).

add vnc mac xx:xx:xx:xx:xx:xx virtual-network-identifier (1-4294967295) vn (A.B.C.D|X:X::X:X) un (A.B.C.D|X:X::X:X) [prefix (A.B.C.D/M|X:X::X:X/M)] [cost (0-255)] [lifetime (infinite|(1-4294967295))]

  Register a MAC address for a logical Ethernet (L2VPN) on behalf of the NVE identified by the VN and UN addresses. The optional prefix parameter is to support enable IP address mediation for the given prefix. The cost parameter provides the administrative preference of the forwarding information. If omitted, it defaults to 255. The lifetime parameter identifies the period, in seconds, that the information remains valid. If omitted, it defaults to infinite.

clear vnc prefix (\*|A.B.C.D/M|X:X::X:X/M) (\*|[(vn|un) (A.B.C.D|X:X::X:X|\*) [(un|vn) (A.B.C.D|X:X::X:X|\*)] [mac xx:xx:xx:xx:xx:xx] [local-next-hop (A.B.C.D|X:X::X:X)])

  Delete the information identified by prefix, VN address, and UN address. Any or all of these parameters may be wildcarded to (potentially) match more than one registration. The optional mac parameter specifies a layer-2 MAC address that must match the registration(s) to be deleted. The optional local-next-hop parameter is used to delete specific local nexthop information.

clear vnc mac (\*|xx:xx:xx:xx:xx:xx) virtual-network-identifier (\*|(1-4294967295)) (\*|[(vn|un) (A.B.C.D|X:X::X:X|\*) [(un|vn) (A.B.C.D|X:X::X:X|\*)] [prefix (\*|A.B.C.D/M|X:X::X:X/M)])

  Delete mac forwarding information. Any or all of these parameters may be wildcarded to (potentially) match more than one registration. The default value for the prefix parameter is the wildcard value *.

clear vnc nve (\*|((vn|un) (A.B.C.D|X:X::X:X) [(un|vn) (A.B.C.D|X:X::X:X)]))

  Delete prefixes associated with the NVE specified by the given VN and UN addresses. It is permissible to specify only one of VN or UN, in which case any matching registration will be deleted. It is also permissible to specify * in lieu of any VN or UN address, in which case all registrations will match.

## Other VNC-Related Commands

Note: VNC-Related configuration can be obtained via the show running-configuration command when in enable mode.

The following commands are used to clear and display Virtual Network Control related information:

clear vnc counters

  Reset the counter values stored by the NVA. Counter values can be seen using the show vnc commands listed above. This command is only available in enable mode.

show vnc summary

  Print counter values and other general information about the NVA. Counter values can be reset using the clear vnc counters command listed below.

show vnc nves

show vnc nves vn|un ADDRESS

  Display the NVA's current clients. Specifying address limits the output to the NVEs whose addresses match address. The time since the NVA last communicated with the NVE, per-NVE summary counters and each NVE's addresses will be displayed.

show vnc queries

show vnc queries PREFIX

  Display active Query information. Queries remain valid for the default Response Lifetime (VNC Defaults Configuration) or NVE-group Response Lifetime (VNC NVE Group Configuration). Specifying prefix limits the output to Query Targets that fall within prefix.

  Query information is provided for each querying NVE, and includes the Query Target and the time remaining before the information is removed.

show vnc registrations [all|local|remote|holddown|imported]

show vnc registrations [all|local|remote|holddown|imported] PREFIX

  Display local, remote, holddown, and/or imported registration information. Local registrations are routes received via RFP, which are present in the NVA Registrations Cache. Remote registrations are routes received via BGP (VPN SAFIs), which are present in the NVE-group import tables. Holddown registrations are local and remote routes that have been withdrawn but whose holddown timeouts have not yet elapsed. Imported information represents routes that are imported into NVA and are made available to querying NVEs. Depending on configuration, imported routes may also be advertised via BGP. Specifying prefix limits the output to the registered prefixes that fall within prefix.

  Registration information includes the registered prefix, the registering NVE addresses, the registered administrative cost, the registration lifetime and the time since the information was registered or, in the case of Holddown registrations, the amount of time remaining before the information is removed.

show vnc responses [active|removed]

show vnc responses [active|removed] PREFIX

  Display all, active and/or removed response information which are present in the NVA Responses Cache. Responses remain valid for the default Response Lifetime (VNC Defaults Configuration) or NVE-group Response Lifetime (VNC NVE Group Configuration.) When Removal Responses are enabled (General VNC Configuration), such responses are listed for the Response Lifetime. Specifying prefix limits the output to the addresses that fall within prefix.

  Response information is provided for each querying NVE, and includes the response prefix, the prefix-associated registering NVE addresses, the administrative cost, the provided response lifetime and the time remaining before the information is to be removed or will become inactive.

show memory vnc

  Print the number of memory items allocated by the NVA.

## Example VNC and VNC-GW Configurations

### Mesh NVA Configuration

This example includes three NVAs, nine NVEs, and two NVE groups. Note that while not shown, a single physical device may support multiple logical NVEs. A three-way full mesh with three NVEs per NVA. shows `code NVA-1` (192.168.1.100), `NVA 2` (192.168.1.101), and `NVA 3` (192.168.1.102), which are connected in a full mesh. Each is a member of the autonomous system 64512. Each NVA provides VNC services to three NVE clients in the 172.16.0.0/16 virtual-network address range. The 172.16.0.0/16 address range is partitioned into two NVE groups, `group1` (172.16.0.0/17) and `group2` (172.16.128.0/17).

Each NVE belongs to either NVE group `group1` or NVE group `group2`. The NVEs `NVE 1`, `NVE 2`, `NVE 4`, `NVE 7`, and `NVE 8` are members of the NVE group `group1`. The NVEs `NVE 3`, `NVE 5`, `NVE 6`, and `NVE 9` are members of the NVE group `group2`.

Each NVA advertises NVE underlay-network IP addresses using the Tunnel Encapsulation Attribute.

A three-way full mesh with three NVEs per NVA.

`bgpd.conf` for `NVA 1` (192.168.1.100):

    router bgp 64512

        bgp router-id 192.168.1.100

        neighbor 192.168.1.101  remote-as 64512
        neighbor 192.168.1.102  remote-as 64512

        address-family ipv4 vpn
            neighbor 192.168.1.101 activate
            neighbor 192.168.1.102 activate
        exit-address-family

        vnc defaults
            rd 64512:1
            response-lifetime 200
            rt both 1000:1 1000:2
        exit-vnc

        vnc nve-group group1
            prefix vn 172.16.0.0/17
            rt both 1000:1
        exit-vnc

        vnc nve-group group2
            prefix vn 172.16.128.0/17
            rt both 1000:2
        exit-vnc

    exit

`bgpd.conf` for `NVA 2` (192.168.1.101):

    router bgp 64512

        bgp router-id 192.168.1.101

        neighbor 192.168.1.100  remote-as 64512
        neighbor 192.168.1.102  remote-as 64512

        address-family ipv4 vpn
            neighbor 192.168.1.100 activate
            neighbor 192.168.1.102 activate
        exit-address-family

        vnc nve-group group1
            prefix vn 172.16.0.0/17
            rd 64512:1
            response-lifetime 200
            rt both 1000:1 1000:2
        exit-vnc
    exit

`bgpd.conf` for `NVA 3` (192.168.1.102):

    router bgp 64512

        bgp router-id 192.168.1.102

        neighbor 192.168.1.101  remote-as 64512
        neighbor 192.168.1.102  remote-as 64512

        address-family ipv4 vpn
            neighbor 192.168.1.100 activate
            neighbor 192.168.1.101 activate
        exit-address-family

        vnc defaults
            rd 64512:1
            response-lifetime 200
            rt both 1000:1 1000:2
        exit-vnc

        vnc nve-group group1
            prefix vn 172.16.128.0/17
        exit-vnc
    exit

### Mesh NVA and VNC-GW Configuration

This example includes two NVAs, each with two associated NVEs, and two VNC-GWs, each supporting two CE routers physically attached to the four NVEs. Note that this example is showing a more complex configuration where VNC-GW is separated from normal NVA functions; it is equally possible to simplify the configuration and combine NVA and VNC-GW functions in a single FRR instance.

Meshed NVEs and VNC-GWs

As shown in Meshed NVEs and VNC-GWs, NVAs and VNC-GWs are connected in a full iBGP mesh. The VNC-GWs each have two CEs configured as route-reflector clients. Each client provides BGP updates with unicast routes that the VNC-GW reflects to the other client. The VNC-GW also imports these unicast routes into VPN routes to be shared with the other VNC-GW and the two NVAs. This route importation is controlled with the `vnc redistribute` statements shown in the configuration. Similarly, registrations sent by NVEs via RFP to the NVAs are exported by the VNC-GWs to the route-reflector clients as unicast routes. RFP registrations exported this way have a next-hop address of the CE behind the connected (registering) NVE. Exporting VNC routes as IPv4 unicast is enabled with the `vnc export` command below.

The configuration for `VNC-GW 1` is shown below.

    router bgp 64512
     bgp router-id 192.168.1.101
     bgp cluster-id 1.2.3.4
     neighbor 192.168.1.102 remote-as 64512
     neighbor 192.168.1.103 remote-as 64512
     neighbor 192.168.1.104 remote-as 64512
     neighbor 172.16.1.2 remote-as 64512
     neighbor 172.16.2.2 remote-as 64512
     !
     address-family ipv4 unicast
      redistribute vnc-direct
      no neighbor 192.168.1.102 activate
      no neighbor 192.168.1.103 activate
      no neighbor 192.168.1.104 activate
      neighbor 172.16.1.2 route-reflector-client
      neighbor 172.16.2.2 route-reflector-client
     exit-address-family
     !
     address-family ipv4 vpn
       neighbor 192.168.1.102 activate
       neighbor 192.168.1.103 activate
       neighbor 192.168.1.104 activate
     exit-address-family
     vnc export bgp mode ce
     vnc redistribute mode resolve-nve
     vnc redistribute ipv4 bgp-direct
     exit

Note that in the VNC-GW configuration, the neighboring VNC-GW and NVAs each have a statement disabling the IPv4 unicast address family. IPv4 unicast is on by default and this prevents the other VNC-GW and NVAs from learning unicast routes advertised by the route-reflector clients.

Configuration for `NVA 2`:

    router bgp 64512
     bgp router-id 192.168.1.104
     neighbor 192.168.1.101 remote-as 64512
     neighbor 192.168.1.102 remote-as 64512
     neighbor 192.168.1.103 remote-as 64512
     !
     address-family ipv4 unicast
      no neighbor 192.168.1.101 activate
      no neighbor 192.168.1.102 activate
      no neighbor 192.168.1.103 activate
     exit-address-family
     !
     address-family ipv4 vpn
       neighbor 192.168.1.101 activate
       neighbor 192.168.1.102 activate
       neighbor 192.168.1.103 activate
     exit-address-family
     !
     vnc defaults
      response-lifetime 3600
      exit-vnc
     vnc nve-group nve1
      prefix vn 172.16.1.1/32
      response-lifetime 3600
      rt both 1000:1 1000:2
      exit-vnc
     vnc nve-group nve2
      prefix vn 172.16.2.1/32
      response-lifetime 3600
      rt both 1000:1 1000:2
      exit-vnc
     exit

### VNC with FRR Route Reflector Configuration

A route reflector eliminates the need for a fully meshed NVA network by acting as the hub between NVAs. Two NVAs and a BGP Route Reflector shows BGP route reflector `BGP Route Reflector 1` (192.168.1.100) as a route reflector for NVAs `NVA 2``(192.168.1.101) and ``NVA 3` (192.168.1.102).

Two NVAs and a BGP Route Reflector

`NVA 2` and `NVA 3` advertise NVE underlay-network IP addresses using the Tunnel Encapsulation Attribute. `BGP Route Reflector 1` `reflects'' advertisements from ``NVA 2` to `NVA 3` and vice versa.

As in the example of Mesh NVA Configuration, there are two NVE groups. The 172.16.0.0/16 address range is partitioned into two NVE groups, `group1` (172.16.0.0/17) and `group2` (172.16.128.0/17). The NVE `NVE 4`, `NVE 7`, and `NVE 8` are members of the NVE group `group1`. The NVEs `NVE 5`, `NVE 6`, and `NVE 9` are members of the NVE group `group2`.

`bgpd.conf` for `BGP Route Reflector 1` on 192.168.1.100:

    router bgp 64512

        bgp router-id 192.168.1.100

        neighbor 192.168.1.101 remote-as 64512
        neighbor 192.168.1.101 port 7179
        neighbor 192.168.1.101 description iBGP-client-192-168-1-101

        neighbor 192.168.1.102 remote-as 64512
        neighbor 192.168.1.102 port 7179
        neighbor 192.168.1.102 description iBGP-client-192-168-1-102

        address-family ipv4 unicast
            neighbor 192.168.1.101 route-reflector-client
            neighbor 192.168.1.102 route-reflector-client
        exit-address-family

        address-family ipv4 vpn
            neighbor 192.168.1.101 activate
            neighbor 192.168.1.102 activate

            neighbor 192.168.1.101 route-reflector-client
            neighbor 192.168.1.102 route-reflector-client
        exit-address-family

    exit

`bgpd.conf` for `NVA 2` on 192.168.1.101:

    router bgp 64512

        bgp router-id 192.168.1.101

        neighbor 192.168.1.100  remote-as 64512

        address-family ipv4 vpn
            neighbor 192.168.1.100 activate
        exit-address-family

        vnc nve-group group1
            prefix vn 172.16.0.0/17
            rd 64512:1
            response-lifetime 200
            rt both 1000:1 1000:2
        exit-vnc
    exit

`bgpd.conf` for `NVA 2` on 192.168.1.102:

    router bgp 64512

        bgp router-id 192.168.1.102

        neighbor 192.168.1.100  remote-as 64512

        address-family ipv4 vpn
            neighbor 192.168.1.100 activate
        exit-address-family

        vnc defaults
            rd 64512:1
            response-lifetime 200
            rt both 1000:1 1000:2
        exit-vnc

        vnc nve-group group1
            prefix vn 172.16.128.0/17
        exit-vnc
    exit

While not shown, an NVA can also be configured as a route reflector.

### VNC with Commercial Route Reflector Configuration

This example is identical to VNC with FRR Route Reflector Configuration with the exception that the route reflector is a commercial router. Only the VNC-relevant configuration is provided.

Two NVAs with a commercial route reflector

`bgpd.conf` for BGP route reflector `Commercial Router` on 192.168.1.104::

    version 8.5R1.13;
    routing-options {
        rib inet.0 {
            static {
                route 172.16.0.0/16 next-hop 192.168.1.104;
            }
        }
        autonomous-system 64512;
        resolution {
            rib inet.3 {
                resolution-ribs inet.0;
            }
            rib bgp.l3vpn.0 {
                resolution-ribs inet.0;
            }
        }
    }
    protocols {
        bgp {
            advertise-inactive;
            family inet {
                labeled-unicast;
            }
           group 1 {
                type internal;
                advertise-inactive;
                advertise-peer-as;
                import h;
                family inet {
                    unicast;
                }
                family inet-vpn {
                    unicast;
                }
                cluster 192.168.1.104;
                neighbor 192.168.1.101;
                neighbor 192.168.1.102;
            }
        }
    }
    policy-options {
        policy-statement h {
            from protocol bgp;
            then {
                as-path-prepend 64512;
                accept;
            }
        }
    }

`bgpd.conf` for `NVA 2` on 192.168.1.101:

    router bgp 64512

        bgp router-id 192.168.1.101

        neighbor 192.168.1.100  remote-as 64512

        address-family ipv4 vpn
            neighbor 192.168.1.100 activate
        exit-address-family

        vnc nve-group group1
            prefix vn 172.16.0.0/17
            rd 64512:1
            response-lifetime 200
            rt both 1000:1 1000:2
        exit-vnc
    exit

`bgpd.conf` for `NVA 3` on 192.168.1.102:

    router bgp 64512

        bgp router-id 192.168.1.102

        neighbor 192.168.1.100  remote-as 64512

        address-family ipv4 vpn
            neighbor 192.168.1.100 activate
        exit-address-family

        vnc defaults
            rd 64512:1
            response-lifetime 200
            rt both 1000:1 1000:2
        exit-vnc

        vnc nve-group group1
            prefix vn 172.16.128.0/17
        exit-vnc
    exit

### VNC with Redundant Route Reflectors Configuration

This example combines the previous two (VNC with FRR Route Reflector Configuration and VNC with Commercial Route Reflector Configuration) into a redundant route reflector configuration. BGP route reflectors `BGP Route Reflector 1` and `Commercial Router` are the route reflectors for NVAs `NVA 2` and `NVA 3`. The two NVAs have connections to both route reflectors.

FRR-based NVA with redundant route reflectors

`bgpd.conf` for `BPGD Route Reflector 1` on 192.168.1.100:

    router bgp 64512

     bgp router-id 192.168.1.100
     bgp cluster-id 192.168.1.100

     neighbor 192.168.1.104 remote-as 64512

     neighbor 192.168.1.101 remote-as 64512
     neighbor 192.168.1.101 description iBGP-client-192-168-1-101
     neighbor 192.168.1.101 route-reflector-client

     neighbor 192.168.1.102 remote-as 64512
     neighbor 192.168.1.102 description iBGP-client-192-168-1-102
     neighbor 192.168.1.102 route-reflector-client

     address-family ipv4 vpn
      neighbor 192.168.1.101 activate
      neighbor 192.168.1.102 activate
      neighbor 192.168.1.104 activate

      neighbor 192.168.1.101 route-reflector-client
      neighbor 192.168.1.102 route-reflector-client
     exit-address-family
    exit

`bgpd.conf` for `NVA 2` on 192.168.1.101:

    router bgp 64512

     bgp router-id 192.168.1.101

     neighbor 192.168.1.100  remote-as 64512
     neighbor 192.168.1.104  remote-as 64512

     address-family ipv4 vpn
      neighbor 192.168.1.100 activate
      neighbor 192.168.1.104 activate
     exit-address-family

     vnc nve-group group1
      prefix vn 172.16.0.0/17
      rd 64512:1
      response-lifetime 200
      rt both 1000:1 1000:2
     exit-vnc
    exit

`bgpd.conf` for `NVA 3` on 192.168.1.102:

    router bgp 64512

     bgp router-id 192.168.1.102

     neighbor 192.168.1.100  remote-as 64512
     neighbor 192.168.1.104  remote-as 64512

     address-family ipv4 vpn
      neighbor 192.168.1.100 activate
      neighbor 192.168.1.104 activate
     exit-address-family

     vnc defaults
      rd 64512:1
      response-lifetime 200
      rt both 1000:1 1000:2
     exit-vnc

     vnc nve-group group1
      prefix vn 172.16.128.0/17
     exit-vnc
    exit

`bgpd.conf` for the Commercial Router route reflector on 192.168.1.104::

    routing-options {
        rib inet.0 {
            static {
                route 172.16.0.0/16 next-hop 192.168.1.104;
            }
        }
        autonomous-system 64512;
        resolution {
            rib inet.3 {
                resolution-ribs inet.0;
            }
            rib bgp.l3vpn.0 {
                resolution-ribs inet.0;
            }
        }
    }
    protocols {
        bgp {
            advertise-inactive;
            family inet {
                labeled-unicast;
            }
           group 1 {
                type internal;
                advertise-inactive;
                advertise-peer-as;
                import h;
                family inet {
                    unicast;
                }
                family inet-vpn {
                    unicast;
                }
                cluster 192.168.1.104;
                neighbor 192.168.1.101;
                neighbor 192.168.1.102;
            }

           group 2 {
                type internal;
                advertise-inactive;
                advertise-peer-as;
                import h;
                family inet {
                    unicast;
                }
                family inet-vpn {
                    unicast;
                }
                neighbor 192.168.1.100;
            }

        }
    }
    policy-options {
        policy-statement h {
            from protocol bgp;
            then {
                as-path-prepend 64512;
                accept;
            }
        }
    }

[1]

The nve-id is carried in the route distinguisher. It is the second octet of the eight-octet route distinguisher generated for Ethernet / L2 advertisements. The first octet is a constant 0xFF, and the third through eighth octets are set to the L2 ethernet address being advertised.