Juniper JUNOSE 11.2.X BGP AND MPLS, Руководство по настройке

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1.
PE 1 sends an MPLS echo request UDP packet that contains an LDP IPv4 sub-TLV.
The packet is sent as a labeled packet over the target LSP. The packet has the
following attributes:
10.1.1.1 Source address
127.0.0.0/8 Destination address
3503 UDP port
255 TTL
10.2.2.2/32 IPv4 prefix in the TLV
Randomly generated 32-bit number used to match the reply Sender’s handle
Integer that is incremented for each echo request packet Sequence number
2.
Router P 1 label-switches the packet to P 2.
3.
Router P 2 label-switches the packet to PE 2 (assuming PHP is not configured).
4.
Router PE 2 pops the label and determines that the destination address is in the
127.0.0.0/8 subnet. PE 2 sends the packet up to the control plane. The MPLS ping
application on the control plane then creates an MPLS echo reply to the received
echo request. The echo reply packet has a return code of 3, which means that the
replying router is an egress for the FEC at stack depth. The echo reply packet includes
the Interface and Label Stack TLV to indicate both the interface on which the request
packet was received and the incoming label stack. The MPLS echo reply packet is
sent back as a (labeled) UDP packet with the following attributes:
10.2.2.2 Source address
10.1.1.1 Destination address
3503 UDP port
5.
When the MPLS echo reply reaches router PE 1, the router matches the sender’s
handle and the sequence number to the echo request packet that PE 1 sent out. If
the values match, the CLI displays an exclamation point (!).
The following sample output represents what you might see when you issue the ping
mpls ip and ping mpls ip detail commands for the topology shown in Figure 67 on page 373.
host1:pe1# ping mpls ip 10.2.2.2/32
Sending 5 UDP echo requests for LDP IPv4 prefix, timeout = 2 sec
!!!!!
Success rate = 100% (5/5), round-trip min/avg/max = 4294967295/4/0 ms
host1:pe1#
ping mpls ip 10.2.2.2/32 detail
Sending 5 UDP echo requests for LDP IPv4 prefix, timeout = 2 sec
MplsNextHopIndex 32 handle 8073311
'!' - success, 'Q' - request not transmitted,
'.' - timeout, 'U' - unreachable,
Copyright © 2010, Juniper Networks, Inc. 374
JunosE 11.2.x BGP and MPLS Configuration Guide