When IGP shortcut is enabled in an IS-IS or an OSPF instance and the family IPv4 is set to resolve over SR-TE LSPs, a hierarchical tunnel is created whereby an LDP IPv4 FEC resolves over the IGP IPv4 shortcuts using SR-TE LSPs.
The following are example outputs of the lsp-trace command for a hierarchical tunnel consisting of a LDP IPv4 FEC resolving over a IGP IPv4 shortcut using a SR-TE LSP.
The topology, as shown in Figure: Example topology for LDP over SR-TE (ISIS) and LDP over SR-TE (OSPF), is used for the following LDP over SR-TE (ISIS) and LDP over SR-TE (OSPF) example outputs.
Figure: Example topology for LDP over SR-TE (ISIS) and LDP over SR-TE (OSPF)
LDP over SR-TE (ISIS) example output:
*A:Dut-F# oam lsp-trace prefix 10.20.1.1/32 detail path-destination 127.1.1.1
lsp-trace to 10.20.1.1/32: 0 hops min, 0 hops max, 184 byte packets
1 10.20.1.4 rtt=2.33ms rc=8(DSRtrMatchLabel) rsc=3
DS 1: ipaddr=10.10.4.2 ifaddr=10.10.4.2 iftype=ipv4Numbered MRU=1492
label[1]=28202 protocol=6(ISIS)
label[2]=28201 protocol=6(ISIS)
label[3]=262138 protocol=3(LDP)
2 10.20.1.2 rtt=6.39m rc=3(EgressRtr) rsc=3
2 10.20.1.2 rtt=7.29ms rc=8(DSRtrMatchLabel) rsc=2
DS 1: ipaddr=10.10.1.1 ifaddr=10.10.1.1 iftype=ipv4Numbered MRU=1492
label[1]=28101 protocol=6(ISIS)
label[2]=262138 protocol=3(LDP)
3 10.20.1.1 rtt=8.34m rc=3(EgressRtr) rsc=2
3 10.20.1.1 rtt=9.37ms rc=3(EgressRtr) rsc=1
*A:Dut-F# oam lsp-ping prefix 10.20.1.1/32 detail
LSP-PING 10.20.1.1/32: 80 bytes MPLS payload
Seq=1, send from intf int_to_D, reply from 10.20.1.1
udp-data-len=32 ttl=255 rtt=8.21ms rc=3 (EgressRtr)
---- LSP 10.20.1.1/32 PING Statistics ----
1 packets sent, 1 packets received, 0.00% packet loss
round-trip mi = 8.21ms, avg = 8.21ms, max = 8.21ms, stddev = 0.000ms
===============================================================================
LDP Bindings (IPv4 LSR ID 10.20.1.6)
(IPv6 LSR ID fc00::a14:106)
===============================================================================
Label Status:
U - Label In Use, N - Label Not In Use, W - Label Withdrawn
WP - Label Withdraw Pending, BU - Alternate For Fast Re-Route
e - Label ELC
FEC Flags:
LF - Lower FEC, UF - Upper FEC, M - Community Mismatch, BA - ASBR Backup FEC
===============================================================================
LDP IPv4 Prefix Bindings
===============================================================================
Prefix IngLbl EgrLbl
Peer EgrIntf/LspId
EgrNextHop
-------------------------------------------------------------------------------
10.20.1.1/32 -- 262138
10.20.1.1:0 LspId 655467
10.20.1.1
10.20.1.1/32 262070U 262040
10.20.1.3:0 --
--
10.20.1.1/32 262070U --
10.20.1.4:0 --
--
10.20.1.1/32 262070U 262091
10.20.1.5:0 --
--
10.20.1.1/32 -- 262138
fc00::a14:101[0] --
--
10.20.1.1/32 262070U 262040
fc00::a14:103[0] --
--
10.20.1.1/32 262070U 262091
fc00::a14:105[0] --
--
-------------------------------------------------------------------------------
No. of IPv4 Prefix Bindings: 7
===============================================================================
LDP over SR-TE (OSPF) example output:
*A:Dut-F# oam lsp-trace prefix 10.20.1.1/32 detail path-destination 127.1.1.1
lsp-trace to 10.20.1.1/32: 0 hops min, 0 hops max, 184 byte packets
1 10.20.1.4 rtt=2.73ms rc=8(DSRtrMatchLabel) rsc=3
DS 1: ipaddr=10.10.4.2 ifaddr=10.10.4.2 iftype=ipv4Numbered MRU=1492
label[1]=27202 protocol=5(OSPF)
label[2]=27201 protocol=5(OSPF)
label[3]=262143 protocol=3(LDP)
2 10.20.1.2 rtt=6.77ms rc=3(EgressRtr) rsc=3
2 10.20.1.2 rtt=6.75ms rc=8(DSRtrMatchLabel) rsc=2
DS 1: ipaddr=10.10.1.1 ifaddr=10.10.1.1 iftype=ipv4Numbered MRU=1492
label[1]=27101 protocol=5(OSPF)
label[2]=262143 protocol=3(LDP)
3 10.20.1.1 rtt=7.10ms rc=3(EgressRtr) rsc=2
3 10.20.1.1 rtt=7.53ms rc=3(EgressRtr) rsc=1
*A:Dut-F# oam lsp-ping prefix 10.20.1.1/32 detail
LSP-PING 10.20.1.1/32: 80 bytes MPLS payload
Seq=1, send from intf int_to_D, reply from 10.20.1.1
udp-data-len=32 ttl=255 rtt=8.09ms rc=3 (EgressRtr)
---- LSP 10.20.1.1/32 PING Statistics ----
1 packets sent, 1 packets received, 0.00% packet loss
round-trip min = 8.09ms, avg = 8.09ms, max = 8.09ms, stddev = 0.000ms
===============================================================================
LDP Bindings (IPv4 LSR ID 10.20.1.6)
(IPv6 LSR ID fc00::a14:106)
===============================================================================
Label Status:
U - Label In Use, N - Label Not In Use, W - Label Withdrawn
WP - Label Withdraw Pending, BU - Alternate For Fast Re-Route
e - Label ELC
FEC Flags:
LF - Lower FEC, UF - Upper FEC, M - Community Mismatch, BA - ASBR Backup FEC
===============================================================================
LDP IPv4 Prefix Bindings
===============================================================================
Prefix IngLbl EgrLbl
Peer EgrIntf/LspId
EgrNextHop
-------------------------------------------------------------------------------
10.20.1.1/32 -- 262143
10.20.1.1:0 LspId 655467
10.20.1.1
10.20.1.1/32 262089U 262135
10.20.1.3:0 --
--
10.20.1.1/32 262089U --
10.20.1.4:0 --
--
10.20.1.1/32 262089U 262129
10.20.1.5:0 --
--
10.20.1.1/32 -- 262143
fc00::a14:101[0] --
--
10.20.1.1/32 262089U 262135
fc00::a14:103[0] --
--
10.20.1.1/32 262089U 262129
fc00::a14:105[0] --
--
-------------------------------------------------------------------------------
No. of IPv4 Prefix Bindings: 7
===============================================================================