Date created: Monday, June 29, 2015 10:27:15 PM. Last modified: Thursday, March 18, 2021 8:10:21 AM
ISIS Basic Multi-Topology
Basic multi-topology IGP using ISIS and SR. Blue topology prefers the northen path, red topology prefers the southern path, black is the default IGP path which is ECMP.
"Using ISIS unicast multi-topology applied to Segment Routing allows users to define multiple overlay topologies. For example, users may want to create a latency optimized topology and a bandwidth optimized topology. Per link is decided if the link is part of a topology and, if so, the metric that link has with in its established topology. The same is the case for loopback prefixes and their associated prefix-SID. This way multiple “overlay” topologies can be tailored over a single physical topology. SPF is calculated in each topology and the resulting shortest paths are downloaded to global FIB. If a prefix exists in multiple topologies, the topology with the lowest index wins."
R1: interface Loopback0 description Loopback ipv4 address 100.0.0.1 255.255.255.255 ! interface Loopback1 ipv4 address 1.1.1.1 255.255.255.255 ! interface Loopback2 ipv4 address 2.2.2.1 255.255.255.255 ! interface GigabitEthernet0/0/0/0 description to xrvr-2 cdp ipv4 address 99.1.2.1 255.255.255.0 ! interface GigabitEthernet0/0/0/1 description to xrvr-8 cdp ipv4 address 99.1.8.1 255.255.255.0 ! router isis 1 is-type level-2-only net 49.0001.0000.0000.0001.00 address-family ipv4 unicast topology red topology-id 8 metric-style wide segment-routing mpls ! address-family ipv4 unicast topology blue topology-id 9 metric-style wide segment-routing mpls ! address-family ipv4 unicast metric-style wide segment-routing mpls ! interface Loopback0 passive address-family ipv4 unicast prefix-sid-value 1 ! ! interface Loopback1 passive address-family ipv4 unicast topology red prefix-sid-value 6111 ! ! interface Loopback2 passive address-family ipv4 unicast topology blue prefix-sid-value 6221 ! ! interface GigabitEthernet0/0/0/0 point-to-point address-family ipv4 unicast topology red metric 100 ! address-family ipv4 unicast topology blue metric 100 ! address-family ipv4 unicast metric 10 ! ! interface GigabitEthernet0/0/0/1 point-to-point address-family ipv4 unicast topology red metric 100 ! address-family ipv4 unicast topology blue metric 100 ! address-family ipv4 unicast metric 10 ! ! ! end R2: interface Loopback0 description Loopback ipv4 address 100.0.0.2 255.255.255.255 ! interface GigabitEthernet0/0/0/0 description to xrvr-1 cdp ipv4 address 99.1.2.2 255.255.255.0 ! interface GigabitEthernet0/0/0/1 description to xrvr-3 cdp ipv4 address 99.2.3.2 255.255.255.0 shutdown ! interface GigabitEthernet0/0/0/2 description to xrvr-8 cdp ipv4 address 99.2.8.2 255.255.255.0 ! router isis 1 is-type level-2-only net 49.0001.0000.0000.0002.00 address-family ipv4 unicast topology red topology-id 8 metric-style wide segment-routing mpls ! address-family ipv4 unicast topology blue topology-id 9 metric-style wide segment-routing mpls ! address-family ipv4 unicast metric-style wide segment-routing mpls ! interface Loopback0 passive circuit-type level-2-only address-family ipv4 unicast ! ! interface GigabitEthernet0/0/0/0 point-to-point address-family ipv4 unicast topology red metric 100 ! address-family ipv4 unicast topology blue metric 100 ! address-family ipv4 unicast metric 10 ! ! interface GigabitEthernet0/0/0/1 point-to-point address-family ipv4 unicast topology red metric 200 ! address-family ipv4 unicast topology blue metric 10 ! address-family ipv4 unicast metric 10 ! ! interface GigabitEthernet0/0/0/2 point-to-point address-family ipv4 unicast topology red metric 10 ! address-family ipv4 unicast topology blue metric 10 ! address-family ipv4 unicast metric 10 ! ! ! end R3: interface Loopback0 description Loopback ipv4 address 100.0.0.3 255.255.255.255 ! interface GigabitEthernet0/0/0/0 description to xrvr-2 cdp ipv4 address 99.2.3.3 255.255.255.0 ! interface GigabitEthernet0/0/0/1 description to xrvr-4 cdp ipv4 address 99.3.4.3 255.255.255.0 shutdown ! interface GigabitEthernet0/0/0/2 description to xrvr-7 cdp ipv4 address 99.3.7.3 255.255.255.0 ! router isis 1 is-type level-2-only net 49.0001.0000.0000.0003.00 address-family ipv4 unicast topology red topology-id 8 metric-style wide segment-routing mpls ! address-family ipv4 unicast topology blue topology-id 9 metric-style wide segment-routing mpls ! address-family ipv4 unicast metric-style wide segment-routing mpls ! interface Loopback0 passive address-family ipv4 unicast prefix-sid-value 3 ! ! interface GigabitEthernet0/0/0/0 point-to-point address-family ipv4 unicast topology red metric 200 ! address-family ipv4 unicast topology blue metric 10 ! address-family ipv4 unicast metric 10 ! ! interface GigabitEthernet0/0/0/1 point-to-point address-family ipv4 unicast topology red metric 100 ! address-family ipv4 unicast topology blue metric 10 ! address-family ipv4 unicast metric 10 ! ! interface GigabitEthernet0/0/0/2 point-to-point address-family ipv4 unicast topology red metric 10 ! address-family ipv4 unicast topology blue metric 10 ! address-family ipv4 unicast metric 10 ! ! ! end R4: interface Loopback0 description Loopback ipv4 address 100.0.0.4 255.255.255.255 ! interface GigabitEthernet0/0/0/0 description to xrvr-3 cdp ipv4 address 99.3.4.4 255.255.255.0 ! interface GigabitEthernet0/0/0/1 description to xrvr-5 cdp ipv4 address 99.4.5.4 255.255.255.0 ! interface GigabitEthernet0/0/0/2 description to xrvr-6 cdp ipv4 address 99.4.6.4 255.255.255.0 ! router isis 1 is-type level-2-only net 49.0001.0000.0000.0004.00 address-family ipv4 unicast topology red topology-id 8 metric-style wide segment-routing mpls ! address-family ipv4 unicast topology blue topology-id 9 metric-style wide segment-routing mpls ! address-family ipv4 unicast metric-style wide segment-routing mpls ! interface Loopback0 passive address-family ipv4 unicast prefix-sid-value 4 ! ! interface GigabitEthernet0/0/0/0 point-to-point address-family ipv4 unicast topology red metric 100 ! address-family ipv4 unicast topology blue metric 10 ! address-family ipv4 unicast metric 10 ! ! interface GigabitEthernet0/0/0/1 point-to-point address-family ipv4 unicast topology red metric 100 ! address-family ipv4 unicast topology blue metric 100 ! address-family ipv4 unicast metric 10 ! ! interface GigabitEthernet0/0/0/2 point-to-point address-family ipv4 unicast topology red metric 10 ! address-family ipv4 unicast topology blue metric 10 ! address-family ipv4 unicast metric 10 ! ! ! end R5: interface Loopback0 description Loopback ipv4 address 100.0.0.5 255.255.255.255 ! interface Loopback1 ipv4 address 1.1.1.2 255.255.255.255 ! interface Loopback2 ipv4 address 2.2.2.2 255.255.255.255 ! interface GigabitEthernet0/0/0/0 description to xrvr-4 cdp ipv4 address 99.4.5.5 255.255.255.0 ! interface GigabitEthernet0/0/0/1 description to xrvr-6 cdp ipv4 address 99.5.6.5 255.255.255.0 ! router isis 1 is-type level-2-only net 49.0001.0000.0000.0005.00 address-family ipv4 unicast topology red topology-id 8 metric-style wide segment-routing mpls ! address-family ipv4 unicast topology blue topology-id 9 metric-style wide segment-routing mpls ! address-family ipv4 unicast metric-style wide segment-routing mpls ! interface Loopback0 passive address-family ipv4 unicast prefix-sid-value 5 ! ! interface Loopback1 passive address-family ipv4 unicast topology red prefix-sid-value 6112 ! ! interface Loopback2 passive address-family ipv4 unicast topology blue prefix-sid-value 6222 ! ! interface GigabitEthernet0/0/0/0 point-to-point address-family ipv4 unicast topology red metric 100 ! address-family ipv4 unicast topology blue metric 100 ! address-family ipv4 unicast metric 10 ! ! interface GigabitEthernet0/0/0/1 point-to-point address-family ipv4 unicast topology red metric 100 ! address-family ipv4 unicast topology blue metric 100 ! address-family ipv4 unicast metric 10 ! ! ! end
R5:
RP/0/0/CPU0:xrvr-5# show isis database verbose xrvr-5
IS-IS 1 (Level-2) Link State Database
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
xrvr-5.00-00 * 0x0000000a 0xc8c9 1105 0/0/0
Area Address: 49.0001
NLPID: 0xcc
MT: Standard (IPv4 Unicast)
MT: TID 8 0/0/0
MT: TID 9 0/0/0
Hostname: xrvr-5
IP Address: 100.0.0.5
Router Cap: 100.0.0.5, D:0, S:0
Segment Routing: I:1 V:0, SRGB Base: 24000 Range: 7999
Metric: 10 IS-Extended xrvr-4.00
Interface IP Address: 99.4.5.5
Neighbor IP Address: 99.4.5.4
ADJ-SID: F:0 B:0 weight:0 Adjacency-sid:32001
Metric: 10 IS-Extended xrvr-6.00
Interface IP Address: 99.5.6.5
Neighbor IP Address: 99.5.6.6
ADJ-SID: F:0 B:0 weight:0 Adjacency-sid:32000
Metric: 10 IP-Extended 99.4.5.0/24
Metric: 10 IP-Extended 99.5.6.0/24
Metric: 0 IP-Extended 100.0.0.5/32
Prefix-SID Index: 5, R:0 N:0 P:0
Metric: 100 MT (TID 8) IS-Extended xrvr-4.00
Interface IP Address: 99.4.5.5
Neighbor IP Address: 99.4.5.4
ADJ-SID: F:0 B:0 weight:0 Adjacency-sid:32001
Metric: 100 MT (TID 8) IS-Extended xrvr-6.00
Interface IP Address: 99.5.6.5
Neighbor IP Address: 99.5.6.6
ADJ-SID: F:0 B:0 weight:0 Adjacency-sid:32000
Metric: 0 MT (TID 8) IP-Extended 1.1.1.2/32
Prefix-SID Index: 6112, R:0 N:0 P:0
Metric: 100 MT (TID 8) IP-Extended 99.4.5.0/24
Metric: 100 MT (TID 8) IP-Extended 99.5.6.0/24
Metric: 100 MT (TID 9) IS-Extended xrvr-4.00
Interface IP Address: 99.4.5.5
Neighbor IP Address: 99.4.5.4
ADJ-SID: F:0 B:0 weight:0 Adjacency-sid:32001
Metric: 100 MT (TID 9) IS-Extended xrvr-6.00
Interface IP Address: 99.5.6.5
Neighbor IP Address: 99.5.6.6
ADJ-SID: F:0 B:0 weight:0 Adjacency-sid:32000
Metric: 0 MT (TID 9) IP-Extended 2.2.2.2/32
Prefix-SID Index: 6222, R:0 N:0 P:0
Metric: 100 MT (TID 9) IP-Extended 99.4.5.0/24
Metric: 100 MT (TID 9) IP-Extended 99.5.6.0/24
Total Level-2 LSP count: 1 Local Level-2 LSP count: 1
R1
RP/0/0/CPU0:xrvr-1#show mpls forwarding
Local Outgoing Prefix Outgoing Next Hop Bytes
Label Label or ID Interface Switched
------ ----------- ------------------ ------------ --------------- ------------
24001 Aggregate No ID default 0
24003 24003 No ID Gi0/0/0/1 99.1.8.8 0
24004 24004 No ID Gi0/0/0/1 99.1.8.8 0
24005 24005 No ID Gi0/0/0/1 99.1.8.8 384
24006 24006 No ID Gi0/0/0/1 99.1.8.8 0
24007 24007 No ID Gi0/0/0/1 99.1.8.8 0
24008 Pop No ID Gi0/0/0/1 99.1.8.8 0
30111 Aggregate No ID default 0
30112 30112 No ID Gi0/0/0/1 99.1.8.8 76800
30221 Aggregate No ID default 0
30222 30222 No ID Gi0/0/0/1 99.1.2.2 0
32000 Pop No ID Gi0/0/0/0 99.1.2.2 0
32001 Pop No ID Gi0/0/0/1 99.1.8.8 0
RP/0/0/CPU0:xrvr-1#show route 100.0.0.5
Routing entry for 100.0.0.5/32
Known via "isis 1", distance 115, metric 40, type level-2
Installed Jun 29 20:53:57.117 for 00:20:57
Routing Descriptor Blocks
99.1.2.2, from 100.0.0.5, via GigabitEthernet0/0/0/0
Route metric is 40
99.1.8.8, from 100.0.0.5, via GigabitEthernet0/0/0/1
Route metric is 40
No advertising protos.
RP/0/0/CPU0:xrvr-1#show route 1.1.1.2/32
Routing entry for 1.1.1.2/32
Known via "isis 1", distance 115, metric 220, type level-2
Installed Jun 29 20:34:51.686 for 00:40:17
Routing Descriptor Blocks
99.1.8.8, from 100.0.0.5, via GigabitEthernet0/0/0/1
Route metric is 220
No advertising protos.
RP/0/0/CPU0:xrvr-1#show route 2.2.2.2/32
Routing entry for 2.2.2.2/32
Known via "isis 1", distance 115, metric 220, type level-2
Installed Jun 29 20:55:10.712 for 00:20:03
Routing Descriptor Blocks
99.1.2.2, from 100.0.0.5, via GigabitEthernet0/0/0/0
Route metric is 220
No advertising protos.
NOW THE LINKS R2-R3 and R3-R4 ARE SHUT DOWN - BLUE TAKES THE SAME PATH AS RED (FOR THE REMAINDER OF THE OUTPUT BELOW)
RP/0/0/CPU0:xrvr-1#show cef 100.0.0.5/32
100.0.0.5/32, version 322, internal 0x4000001 0x0 (ptr 0xace1da20) [1], 0x0 (0xace05538), 0x450 (0xacdb93d8)
Updated Jun 29 20:53:57.138
local adjacency 99.1.8.8
Prefix Len 32, traffic index 0, precedence n/a, priority 1
via 99.1.8.8, GigabitEthernet0/0/0/1, 7 dependencies, weight 0, class 0 [flags 0x0]
path-idx 0 NHID 0x0 [0xacaf6d80 0x0]
next hop 99.1.8.8
local adjacency
local label 24005 labels imposed {24005}
RP/0/0/CPU0:xrvr-1#show cef 1.1.1.2/32
1.1.1.2/32, version 304, internal 0x4000001 0x0 (ptr 0xace1d8a0) [1], 0x0 (0xace053ac), 0x450 (0xacdb92c0)
Updated Jun 29 20:34:51.715
local adjacency 99.1.8.8
Prefix Len 32, traffic index 0, precedence n/a, priority 1
via 99.1.8.8, GigabitEthernet0/0/0/1, 7 dependencies, weight 0, class 0 [flags 0x0]
path-idx 0 NHID 0x0 [0xacaf6d80 0x0]
next hop 99.1.8.8
local adjacency
local label 30112 labels imposed {30112}
RP/0/0/CPU0:xrvr-1#show cef 2.2.2.2/32
2.2.2.2/32, version 353, internal 0x4000001 0x0 (ptr 0xace1d920) [1], 0x0 (0xace055a4), 0x450 (0xacdb9388)
Updated Jun 29 20:55:10.733
local adjacency 99.1.8.8
Prefix Len 32, traffic index 0, precedence n/a, priority 1
via 99.1.8.8, GigabitEthernet0/0/0/1, 7 dependencies, weight 0, class 0 [flags 0x0]
path-idx 0 NHID 0x0 [0xacaf6d80 0x0]
next hop 99.1.8.8
local adjacency
local label 30222 labels imposed {30222}
R2
RP/0/0/CPU0:xrvr-2# show mpls forwarding
Local Outgoing Prefix Outgoing Next Hop Bytes
Label Label or ID Interface Switched
------ ----------- ------------------ ------------ --------------- ------------
24001 Pop No ID Gi0/0/0/0 99.1.2.1 0
24003 24003 No ID Gi0/0/0/2 99.2.8.8 0
24004 24004 No ID Gi0/0/0/2 99.2.8.8 0
24005 24005 No ID Gi0/0/0/2 99.2.8.8 0
24006 24006 No ID Gi0/0/0/2 99.2.8.8 0
24007 24007 No ID Gi0/0/0/2 99.2.8.8 0
24008 Pop No ID Gi0/0/0/2 99.2.8.8 0
30111 Pop No ID Gi0/0/0/0 99.1.2.1 0
30112 30112 No ID Gi0/0/0/2 99.2.8.8 0
30221 Pop No ID Gi0/0/0/0 99.1.2.1 0
30222 30222 No ID Gi0/0/0/2 99.2.8.8 0
32000 Pop No ID Gi0/0/0/0 99.1.2.1 0
32002 Pop No ID Gi0/0/0/2 99.2.8.8 0
RP/0/0/CPU0:xrvr-1#traceroute 1.1.1.2
Type escape sequence to abort.
Tracing the route to 1.1.1.2
1 99.1.8.8 [MPLS: Label 30112 Exp 0] 39 msec 29 msec 19 msec
2 99.7.8.7 [MPLS: Label 30112 Exp 0] 19 msec 19 msec 29 msec
3 99.6.7.6 [MPLS: Label 30112 Exp 0] 39 msec 19 msec 39 msec
4 99.5.6.5 19 msec * 29 msec
RP/0/0/CPU0:xrvr-1#traceroute 2.2.2.2
Type escape sequence to abort.
Tracing the route to 2.2.2.2
1 99.1.8.8 [MPLS: Label 30222 Exp 0] 29 msec 29 msec 19 msec
2 99.7.8.7 [MPLS: Label 30222 Exp 0] 29 msec 39 msec 29 msec
3 99.6.7.6 [MPLS: Label 30222 Exp 0] 29 msec 29 msec 19 msec
4 99.5.6.5 29 msec * 29 msec
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