Extended communities

Extended communities serve specialized roles. Each extended community is eight bytes. The first one or two bytes identifies the type or sub-type and the remaining six or seven bytes identify a value. Some of the more common extended communities supported by SR OS include:

• Transitive 2-octet AS-specific

  • Route target (type 0x0002)

  • Route origin (type 0x0003)

  • OSPF domain ID (type 0x0005)

  • Source AS (type 0x0009)

  • L2VPN identifier (type 0x000A)

• Non-transitive 2-octet AS-specific

  Link bandwidth (0x4004)

• Transitive 4-octet AS-specific

  • Route target (type 0x0202)

  • Route origin (type 0x0203)

  • OSPF domain ID (type 0x0205)

  • Source AS (type 0x0209)

• Transitive IPv4-address-specific

  • Route target (type 0x0102)

  • Route origin (type 0x0103)

  • OSPF domain ID (type 0x0105)

  • L2VPN identifier (type 0x010A)

  • VRF route import (type 0x010B)

• Transitive opaque

  • OSPF route type (type 0x0306)

  • Color extended community (type 0x030B)

• Non-transitive opaque

  BGP origin validation state (type 0x4300)

• Transitive experimental

  • FlowSpec traffic rate (type 0x8006)

  • FlowSpec traffic action (type 0x8007)

  • FlowSpec redirect (type 0x8008)

  • FlowSpec traffic-remarking (0x8009)

  • Layer 2 info (type 0x800A)

• Transitive FlowSpec

  FlowSpec interface-set (type 0x0702)

• Non-transitive FlowSpec

  FlowSpec interface-set (type 0x4702)

Extended communities can be added to or removed from BGP routes using BGP import and export policies. When a BGP route is locally originated by exporting a static or aggregate route into BGP, and the static or aggregate route has one or more extended communities, these community values are automatically added to the BGP route.

To remove all the extended communities from all routes advertised to a BGP peer, use the disable-communities extended command.