H3C Technologies H3C S5560 Series Switches - Manual (Page 260)

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Step Command Remarks
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. ip vpn-instance
vpn-instance-name
N/A
3. Enable BGP to establish an
EBGP session to an
indirectly-connected peer or
peer group and specify the
maximum hop count.
peer { group-name | ipv6-address
[ prefix-length ] } ebgp-max-hop
[ hop-count ]
By default, BGP cannot establish
an EBGP session to an
indirectly-connected peer or peer
group.
Enabling immediate re-establishment of direct EBGP
connections upon link failure
When the link to a directly-connected EBGP peer goes down, the router does not re-establish a session
to the peer until the hold time timer expires. This feature enables BGP to immediately recreate the session
in that situation. When this feature is disabled, route flapping does not affect EBGP session state.
To enable immediate re-establishment of direct EBGP connections:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter BGP view. bgp as-number N/A
3. Enable immediate re-establishment of
direct EBGP connections upon link
failure. ebgp-interface-sensitive
By default, this feature is
enabled.
Enabling 4-byte AS number suppression
BGP supports 4-byte AS numbers. The 4-byte AS number occupies four bytes, in the range of 1 to
4294967295. By default, a device sends an Open message to the peer device for session establishment.
The Open message indicates that the device supports 4-byte AS numbers. If the peer device supports
2-byte AS numbers instead of 4-byte AS numbers, the session cannot be established. To resolve this issue,
enable the 4-byte AS number suppression function. The device then sends an Open message to inform
the peer that it does not support 4-byte AS numbers, so 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 session cannot be established.
To enable 4-byte AS number suppression (IPv4):
Step Command Remarks
1. Enter system view. system-view N/A