Foundry NetIron M2404C and M2404F Metro Access Switches
Configuring MPLS and H-VPLS (Rev. 03)
Multiprotocol Label Switching
© 2008 Foundry Networks, Inc
Page 23 of 113
Both the MPLS echo request and MPLS echo reply are User Datagram Protocol (UDP) packets
with source and destination ports set to 3503. To validate an LSP, the LSP Ping uses MPLS echo
request and reply packets.
The MPLS echo request packet is sent to a target router using the appropriate label stack which is
associated with the LSP to be validated. This causes the packet to be sent through the LSP.
The IP destination address of the MPLS echo request packet is different from the address used to
select the label stack. The destination address of the UDP packet is defined as the 127.
x
.
y
.
z
/8
address. In case that the LSP is broken, the IP packet will not be IP-switched to its destination.
An MPLS echo reply is sent, as IP packet, in response to an MPLS echo request. Then it is
forwarded using IP, MPLS, or a combination of both types of switching.
The source address of the MPLS echo reply packet is an address from the router generating the
echo reply. The destination address is the source address of the router in the MPLS echo request
packet.
Command Syntax
device-name
#
mpls lsp-ping
[
lsp
LSP-NAME
|
prefix
A.B.C.D/M
] [
size
<
octets
>] [
ttl <label-ttl>
] [
count
<
count
>] [
timeout
<
timeout
>] [
draft3
|
rfc
]
Argument Description
lsp LSP-NAME
(Optional). Specifies the name of the LSP to ping.
prefix A.B.C.D/M
(Optional). Specifies the prefix of the Forwarding Equivalence Class
(FEC), the egress of which will be pinged.
size <octets>
(Optional). Specifies the minimum packet size in octets. The range
is <60-1300>. The packet is padded with NULL characteristics to
the specified size. The default value is 48. The maximum packet size
is 1300.
ttl <label-ttl>
(Optional). Indicates the maximum number of hops that the MPLS
packet should take to reach the specified IP address in range <1-
255>. The default TTL (time-to-live) is 64.
The TTL field in the MPLS label is decremented by 1 at each hop.
When the TTL value drops below one, the packet is discarded.
timeout <timeout>
(Optional). Number of seconds to wait for a connectivity test reply.
The range is <1-120> seconds. The default value is 2 seconds.
count <count>
(Optional). Number of messages to be sent. The default value is 1.
The range is <1-100>
draft3
(Optional). Sets a packet format compliant with draft 3 of the LSP
Ping specification.
rfc
(Optional). Sets a packet format compliant with RFC4379.
Example 1 (Successful lsp ping)
device-name
#
mpls lsp-ping lsp tunnel1 count 20
Sending 20 packet(s), timeout is 2 sec:
Legend: X - error, . - timeout, R - transit, ! - egress
Press Esc for break
!!!!!!!!!!!!!!!!!!!!
20 packets sent, 20 packets received, 0% packet loss
round-trip min/avg/max = 10/10/20 ms