334
Step Command
Remarks
3.
Enter IPv6 address family
view.
ipv6-family
N/A
4.
Allow the local AS number to
appear in AS_PATH of routes
from a peer or peer group
and specify the repeat times.
peer
{
ipv6-group-name
|
ipv6-address
}
allow-as-loop
[
number
]
Optional.
Not allowed by default.
5.
Specify a fake AS number for
an IPv6 peer or peer group.
peer
{
ipv6-group-name
|
ipv6-address
}
fake-as
as-number
Optional.
Not specified by default.
6.
Disable IPv6 BGP from
considering the AS_PATH
during best route selection.
bestroute as-path-neglect
Optional.
Enabled by default.
7.
Configure to carry only the
public AS number in updates
sent to a peer or peer group.
peer
{
ipv6-group-name
|
ipv6-address
}
public-as-only
Optional.
By default, IPv6 BGP updates carry
a private AS number.
8.
Substitute the local AS number
for the AS number of an IPv6
peer or peer group identified
in the AS_PATH attribute.
peer
{
ipv6-group-name
|
ipv6-address
}
substitute-as
Optional.
Not substituted by default.
Tuning and optimizing IPv6 BGP networks
This section describes configurations of IPv6 BGP timers, IPv6 BGP connection soft reset, and the
maximum number of load balanced routes.
•
IPv6 BGP timers
After establishing an IPv6 BGP connection, two routers send keepalive messages periodically to
each other to maintain the connection. If a router receives no keepalive message from the peer
after the holdtime elapses, it tears down the connection.
When establishing an IPv6 BGP connection, the two parties compare their holdtimes, taking the
shorter one as the common holdtime. If the holdtime is 0, neither keepalive massage is sent, nor
holdtime is checked.
•
IPv6 BGP connection soft reset
After modifying a route selection policy, you must reset IPv6 BGP connections to make the new one
take effect. The current IPv6 BGP implementation supports the route-refresh feature that enables
dynamic route refresh without needing to disconnect IPv6 BGP links.
After this feature is enabled on all IPv6 BGP routers, a router that wants to apply a new route
selection policy advertises a route-refresh message to its peers, which then send their routing
information to the router. After receiving the routing information, the router can perform dynamic
route update by using the new policy without tearing down connections.
If a peer not supporting route-refresh exists in the network, you must configure the
peer
keep-all-routes
command to save all routes from the peer. When the routing policy is changed, the
system will update the IPv6 BGP routing table and apply the new policy.
