Administrator Guide

1352 BGP
In order for two BGP speakers to exchange labeled VPN-IPv4 NLRI, they
must use the BGP Capabilities Advertisement (in the OPEN message) to
ensure that they both are capable of properly processing VPN-IPv4 NLRI.
This is done by using capability code 1 (multiprotocol BGP), with an AFI of 1
and an SAFI of 128.
The VPNv4 NLRI is encoded as specified in the above sections, where the
prefix consists of an 8-byte RD followed by an IPv4 prefix.
The Site of Origin Attribute (SOO)
A VPNv4 route may optionally carry a Site of Origin attribute that uniquely
identifies a site (a topologically associated set of routers with mutual IP
connectivity). This attribute identifies the corresponding route as having
come from one of the site members.
The SOO attribute is used in the identification and prevention of routing
loops. The SOO attribute is an extended community attribute used to
identify routes that have originated from a site so that the re-advertisement of
that prefix back to the source site can be prevented, thereby helping to
eliminate routing loops.
Site of Origin is one of the attributes a router assigns to a prefix prior to
redistributing any VPNv4 prefixes. All prefixes learned from a particular site
must be assigned the same site of origin attribute, even if the site is multiply
connected to a single router external to the site or is connected to multiple
routers external to the site.
Dell Networking allows configuration of the SOO attribute using IP
Extended community lists in association with inbound/outbound route maps.
IPv6
Dell Networking supports both IPv4 and IPv6 peering sessions. IPv4 routes
are advertised on IPv4 peer sessions. Dell Networking does not support
advertisement of IPv4 routes over IPv6 peer sessions. IPv6 routes can be
advertised over either type of peer session as described in RFC 4760 and RFC
2545. The user must explicitly activate IPv6 route advertisement on either
type of peer session. When IPv6 is enabled, the OPEN message includes the
IPv6/unicast AFI/SAFI pair in the multiprotocol capability option.