H3C Technologies H3C S12500 Series Switches - Manual (Page 248)

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After you enable the 4-byte AS number suppression function, the peer device can then process the Open
message even though it does not support 4-byte AS numbers, and the BGP session can be established.
If the peer device supports 4-byte AS numbers, do not enable the 4-byte AS number suppression function;
otherwise, the BGP peer relationship cannot be established.
To enable 4-byte AS number suppression:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter BGP view or BGP-VPN
instance view.
• Enter BGP view:
bgp as-number
• Enter BGP-VPN instance view:
a. bgp as-number
b. ipv4-family vpn-instance
vpn-instance-name
Use either method.
3. Enable 4-byte AS number
suppression.
peer { group-name | ip-address }
capability-advertise
suppress-4-byte-as Disabled by default.
Enabling quick reestablishment of direct EBGP session
When the link to a directly connected EBGP peer is down, the router, with quick EBGP session
reestablishment enabled, will tear down the session to the peer, and then reestablish a session
immediately. If the function is not enabled, the router does not tear down the session until the holdtime
times out. A route flap will not affect the EBGP session state when the quick EBGP session reestablishment
is disabled.
To enable quick reestablishment of direct EBGP session:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter BGP view or BGP-VPN
instance view.
• Enter BGP view:
bgp as-number
• Enter BGP-VPN instance view:
a. bgp as-number
b. ipv4-family vpn-instance
vpn-instance-name
Use either method.
3. Enable quick reestablishment
of direct EBGP session.
ebgp-interface-sensitive
Optional.
Not enabled by default.
Enabling MD5 authentication for TCP connections
You can enable MD5 authentication to enhance security in the following ways:
• Perform MD5 authentication when establishing TCP connections. Only the two parties that have the
same password configured can establish TCP connections.
• Perform MD5 calculation on TCP packets to avoid modification to the encapsulated BGP packets.