Accton Technology ES4626 - Manual (Page 550)

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Function: Configures the EBGP neighbors can existing in different segment as well as its
hop count (TTL). The “no neighbor {|} ebgp-multihop [<1-255>]”
set that the EBGP neighbors must be in the same segment
Parameter: : Neighbor IP address
: Name of the peer group
<1-255>: Allowed hop count
Default: Must be in the same segment
Command Mode: BGP route mode and address-family mode
Usage Guide:
Without this command, EBGP peers are required to be in the same
segment and after this command is configured, peer addresses may from different
segments. The allowed hop count can be configured and will be 255 if not.
Example:
Three device 10.1.1.64(AS100) and 11.1.1.120(AS300) connected respectively to the two
interface 10.1.1.66 and 10.1.1.100 of another device. IGP accessibilities of 10.1.1.64 and
11.1.1.120 on both side routes are ensured through static configuration. The neighbor
relationship is established only after both side are configured as follows:
on 10.1.1.64
Switch(config-router)#neighbor 11.1.1.120 ebgp-multihop
on 11.1.1.120
Switch(config-router)#neighbor 10.1.1.64 ebgp-multihop
After this, switches in different segments will be able to create BGP neighbor relationship
13.8.3.54 neighbor enforce-multihop
Command: neighbor {|} enforce-multihop
no neighbor {|} enforce-multihop
Function: Enforce the multihop connection to the neighbor. The “no neighbor
{|} enforce-multihop ” command cancels this configuration
Parameter: : Neighbor IP address
: Name of peer group
Default:
Not enforced
Command Mode: BGP mode and address-family mode
Usage Guide: In fact the direct route can not be enforced to multihop, however will be
treated as a multihop connection with this configuration, namely the check originally only
performed on IBGP and EBGP of non-direct routes will be performed on all after this
attribute set. The nexthop direct connected check will not be performed at exit in enforce
multihop conditions.
Example:
Switch(config-router)#neighbor 10.1.1.66 enforce-multihop