— Exhibit — Click the Exhibit button. A customer is trying to configure a router to peer using
EBGP to a neighbor. As shown in the exhibit, two links are being used for this configuration.
The goal of this configuration is to loadbalance traffic across both EBGP links. Which
configuration accomplishes this goal?
A.
{master:0}[edit] user@router# show protocols bgp group External { multihop;
local-address 192.168.2.1; peer-as 65532; neighbor 10.10.2.2; neighbor 10.20.2.2; }
{master:0}[edit] user@router# show routing-options static { route 192.168.5.1/32 next-hop
192.168.2.1; } autonomous-system 65432;
B.
{master:0}[edit] user@router# show protocols bgp group External { multihop;
local-address 192.168.2.1; peer-as 65532; neighbor 192.168.5.1; } {master:0}[edit]
user@router# show routing-options static { route 192.168.5.1/32 next-hop [ 10.10.2.2
10.20.2.2 ]; } autonomous-system 65432; forwarding-table { export load-balance; }
{master:0}[edit] user@router# show policy-options policy-statement load-balance term
balance { then { load-balance per-packet; accept; } }
C.
{master:0}[edit] user@router# show protocols bgp group External { multi-path;
local-address 192.168.2.1; peer-as 65532; neighbor 192.168.5.1; } {master:0}[edit]
user@router# show routing-options static { route 192.168.5.1/32 next-hop [ 10.10.2.2
10.20.2.2 ]; } autonomous-system 65432;
D.
{master:0}[edit] user@router# show protocols bgp group External { multipath;
local-address 192.168.2.1; peer-as 65532; neighbor 10.10.2.2; neighbor 10.20.2.2; }
{master:0}[edit] user@router# show routing-options static { route 192.168.5.1/32 next-hop
192.168.2.1; } autonomous-system 65432;
2. The default behavior for an EBGP connection is to peer over a single physical hop using the physical interface address of the peer. In some cases, it is advantageous to alter this default, one-hop, physical peering EBGP behavior. One such case is when multiple physical links connect two routers that are to be EBGP peers. In this case, if one of the point-to-point links fails, reachability on the alternate link still exists.
EBGP Multihop Peering
In figure 1, router R1 belongs to AS 1 and router R2 belongs to AS 2. The two physical links between the routers is used for load balancing. The EBGP multihop peering works with one physical link as well.
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