Filter
Top Products
Configuring BGP for IPv6 Configuring BGP
page 4-74 OmniSwitch 6800/6850/9000 Advanced Routing Configuration Guide December 2007
Local Preference
Local preference is an attribute that specifies the degree of preference to be given to a specific route when
there are multiple routes to the same destination. This attribute is propagated throughout the autonomous
system and is represented by a numeric value. The higher the number, the higher the preference. For
example, a route with two exits, one with a local preference of 50 and another with a local preference 30
will use the path which has the local preference of 50.
To set the local preference for the local network, enter the IPv6 address and mask of the local network in
conjunction with the ipv6 bgp network local-preference command and value, as shown:
-> ipv6 bgp network 2001::1/64 local-preference 600
The local preference for routes generated by the network is now 600. The default value is 0 (no network
local preference is set).
Community
Communities are a way of grouping BGP destination addresses that share some common property. Adding
the local network to a specific community indicates that the network shares a common set of properties
with the rest of the community.
To add a network to a community, enter the local network IPv6 address and mask in conjunction with the
ipv6 bgp network community command and name, as shown:
-> ipv6 bgp network 2001::1/64 community 100:200
Network 2001::1/64 is now in the 100:200 community. The default community is no community.
To remove the local network from the community, enter the local network as above with the community
set to “none”, as shown:
-> ipv6 bgp network 2001::1/64 community none
The network is now no longer in any community.
Metric
A metric for an IPv6 network is the Multi-Exit Discriminator (MED) value. This value is sent from rout-
ers of one AS to another to indicate the path that the remote AS can use to send data to the local AS
assuming there is more than one. A lower value indicates a more preferred exit point. For example, a route
with a MED of 10 is more likely to be used than a route with an MED of 100.
To set the network metric value, enter the network IPv6 address and mask in conjunction with the ipv6
bgp network metric command and value, as shown:
-> ipv6 bgp network 2001::1/64 metric 100
The IPv6 network 2001::1/64 is now set with a metric of 100. The default metric is 0.