HP VPN Firewall Appliances Network Management Configuration Guide

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forwards the packet to Router C through route recursion. Router C does not know the route 8.0.0.0/8, so

it discards the packet.

Figure 293 BGP and IGP synchronization in an AS

For this example, if synchronization is enabled, and the route 8.0.0.0/24 received from Router B is

available in its IGP routing table, Router D advertises the IBGP route when the following conditions are

met:

• The next hop of the route is reachable.

• An active route with the same destination network segment is available in the IGP routing table (use

the display ip routing-table protocol command to check the IGP route state).

You can disable the synchronization feature in the following situations:

• The local AS is not a transitive AS (AS 20 is a transitive AS in the above figure).

• Routers in the local AS are IBGP fully meshed.

To enable BGP and IGP synchronization:

Ste

Command

Remarks

1. Enter system view.

system-view N/A

2. Enter BGP view.

bgp as-number N/A

3. Enable synchronization

between BGP and IGP.

synchronization Not enabled by default.

Limiting prefixes received from a peer or peer group

This feature can prevent that send a large number of BGP routes to the router.

If the number of routes received from a peer or peer group exceeds the upper limit, the router takes one

of the following actions based on your configuration:

• Tear down the BGP session to the peer or peer group.

• Display an alarm message.

• Tear down the BGP session to the peer or peer group and, after a specified period of time,

reestablishes a BGP session to the peer or peer group.

You can specify the threshold value for the router to display an alarm message. When the ratio of the

number of received routes to the maximum number reaches the percentage value, the router displays an

alarm message.

To configure the maximum number of prefixes allowed to be received from a peer or peer group: