H3C Technologies H3C S5560 Series Switches - Manual (Page 264)

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Disabling BGP to establish a session to a peer or peer group
This task enables you to temporarily tear down the BGP session to a specific peer or peer group. Then
you can perform network upgrade and maintenance without needing to delete and reconfigure the peer
or peer group. To recover the session, execute the undo peer ignore command.
To disable BGP to establish a session to a peer or peer group (IPv4):
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. ip vpn-instance
vpn-instance-name
N/A
3. Disable BGP to establish a
session to a peer or peer
group.
peer { group-name | ip-address
[ mask-length ] } ignore By default, BGP can establish a
session to a peer or peer group.
To disable BGP to establish a session to a peer or peer group (IPv6):
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. ip vpn-instance
vpn-instance-name
N/A
3. Disable BGP to establish a
session to a peer or peer
group.
peer { group-name | ipv6-address
[ prefix-length ] } ignore By default, BGP can establish a
session to a peer.
Configuring GTSM for BGP
IMPORTANT:
•
When GTSM is configured, the local device can establish an EBGP session with the peer after both
devices pass GTSM check, regardless of whether the maximum number of hops is reached.
• To use GTSM, you must configure GTSM on both the local and peer devices. You can specify different
hop-count values for them.
The Generalized TTL Security Mechanism (GTSM) protects a BGP session by comparing the TTL value in
the IP header of incoming BGP packets against a valid TTL range. If the TTL value is within the valid TTL
range, the packet is accepted. If not, the packet is discarded.
The valid TTL range is from 255 – the configured hop count + 1 to 255.