Alcatel-Lucent 7210 SAS M User Manual page 39

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In IP-encapsulation, LSP-Ping packets are sent over the MPLS LSP for which OAM is being
performed and contain an IP/UDP packet within them. The On-demand CV echo response
message is sent on the reverse path of the LSP, and the reply contains IP/UDP headers followed by
the On-demand CV payload.
In non-IP environments, LSP ping can be encapsulated with no IP/UDP headers in a G-ACh and
use a source address TLV to identify the source node, using forward and reverse LSP or PW
associated channels on the same LSP or PW for the echo request and reply packets. In this case, no
IP/UDP headers are included in the LSP-Ping packets.
The 7210 supports the following encapsulations:
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LSP Ping and VCCV Ping for MPLS-TP use two new FEC sub-types in the target FEC stack in
order to identify the static LSP or static PW being checked. These are the Static LSP FEC sub-
type, which has the same format as the LSP identifier described above, and the Static PW FEC
sub-type,. These are used in-place of the currently defined target FEC stack sub-TLVs.
In addition, MPLS-TP uses a source/destination TLV to carry the MPLS-TP global-id and node-id
of the target node for the LSP ping packet, and the source node of the LSP ping packet.
LSP Ping and VCCV-Ping for MPLS-TP can only be launched by the LER or T-PE. The replying
node therefore sets the TTL of the LSP label or PW label in the reply packet to 255 to ensure that
it reaches the node that launched the LSP ping or VCCV Ping request.
Downstream Mapping Support
RFC4379 specifies four address types for the downstream mapping TLV for use with IP numbered
and unnumbered interfaces:
7210 SAS M, T, X, R6, Mxp MPLS Configuration Guide
IP encapsulation, using the same label stack as RFC4379, or encapsulated in the IPv4 G-
ACh channel with a GAL/ACH
A non-IP encapsulation with GAL/ACH for LSPs and ACH for PWs.
IP encapsulation with ACH for PWs (as per VCCV type 1).
IP encapsulation without ACH for LSPs using labeled encapsulation
Non-IP encapsulation with ACH for both PWs and LSPs.
MPLS and RSVP
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