Cisco ASR 900 Series User Manual

The figure below shows the echo request and echo reply paths for MPLS LSP Ping.
Figure 6: MPLS LSP Ping Echo Request and Echo Reply Paths
If you initiate an MPLS LSP Ping request at LSR1 to a Forwarding Equivalence Class (FEC), at LSR6, you
get the results shown in the table below .
Table 4: MPLS LSP Ping Example
ActionDeviceStep
Initiates an MPLS LSP Ping
request for an FEC at the target
device LSR6 and sends an MPLS
echo request to LSR2.
LSR1
1
Receives and forwards the MPLS
echo request packet through transit
devices LSR3 and LSR4 to the
penultimate device LSR5.
LSR2
1
Receives the MPLS echo request,
pops the MPLS label, and forwards
the packet to LSR6 as an IP packet.
LSR5
1
Receives the IP packet, processes
the MPLS echo request, and sends
an MPLS echo reply to LSR1
through an alternate route.
LSR6
1
Receive and forward the MPLS
echo reply back toward LSR1, the
originating device.
LSR7 to LSR10
1
Receives the MPLS echo reply in
response to the MPLS echo
request.
LSR1
1
MPLS Basic Configuration Guide, Cisco IOS XE Everest 16.5.1 (Cisco ASR 900 Series)
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MPLS LSP Ping, Traceroute, and AToM VCCV
MPLS LSP Ping Operation

Cisco ASR 900 Series Specifications

General

Brand	Cisco
Model	ASR 900 Series
Category	Network Router
Language	English