Adjusting And Optimizing A Bgp Network - 3Com 7757 Configuration Manual

Adjusting and
Optimizing a BGP
Network
Configuration
Prerequisites
Adjusting and optimizing BGP network involves the following aspects:
1 BGP clock
BGP peers send Keepalive messages to each other periodically through the
connections between them to make sure the connections operate properly. If a
router does not receive the Keepalive or any other message from its peer in a
specific period (know as Holdtime), the router considers the BGP connection
operates improperly and thus disconnects the BGP connection.
When establishing a BGP connection, the two routers negotiate for the Holdtime
by comparing their Holdtime values and take the smaller one as the Holdtime.
2 Limiting the number of route prefixes to be received from the peer/peer group
By limiting the number of route prefixes to be received from the specified
peer/peer group, you can control the size of the local routing table, thus
optimizing the performance of local router system and protecting local routers.
When the number of route prefixes received exceeds the configured value, a
router enabled with this function is automatically disconnected from the peer/peer
group.
3 BGP connection reset
To make a new BGP routing policy taking effect, you need to reset the BGP
connection. This temporarily disconnects the BGP connection. In the Switch 7750,
BGP supports the route-refresh function. With route-refresh function enabled on
all the BGP routers, if BGP routing policy changes, the local router sends refresh
messages to its peers. And the peers receiving the message in turn send their
routing information to the local router. In this way, you can apply new routing
policies and have the routing table dynamically updated seamlessly.
Use the refresh bgp command to reset the BGP connections manually. This
method can also refresh BGP routing tables and apply a new routing policy
seamlessly.
4 BGP authentication
BGP uses TCP as the transport layer protocol. To improve the security of BGP
connections, you can specify to perform MD5 authentication when a TCP
connection is established. Note that the MD5 authentication of BGP does not
authenticate the BGP packets. It only configures the MD5 authentication
password for TCP connection, and the authentication is performed by TCP. If
authentication fails, the TCP connection cannot be established.
You need to perform the following configuration before adjusting the BGP clock.
Enable basic BGP functions
■
Before configuring BGP clock and authentication, make sure the following
information is available.

Adjusting and Optimizing a BGP Network

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