Hi everyone,
I have the following flex-algo lab:
I have configured 3 flex algos on PE1 as follows:
router isis ISIS1 is-type level-2-only net 49.0001.0100.0000.0001.00 distribute link-state affinity-map RED bit-position 20 affinity-map GREEN bit-position 10 address-family ipv4 unicast metric-style wide advertise passive-only mpls traffic-eng level-2-only mpls traffic-eng router-id Loopback0 segment-routing mpls sr-prefer ! address-family ipv6 unicast metric-style wide advertise passive-only router-id Loopback0 single-topology segment-routing mpls sr-prefer ! flex-algo 140 priority 255 advertise-definition affinity include-all GREEN ! flex-algo 150 priority 255 advertise-definition affinity include-all RED ! flex-algo 160 priority 255 advertise-definition affinity exclude-any GREEN !
Assume the link colors on the interfaces match what is shown in the screenshot (so for example P1 has Gi0/0/0/0 and Gi0/0/0/2 are GREEN, Gi0/0/0/3 are RED and Gi0/0/0/4 is uncolored).
There are no other flex-aglo definitions advertised by any other router.
The SID indices are defined as follows:
interface Loopback0 address-family ipv4 unicast prefix-sid index x prefix-sid algorithm 140 index 14x prefix-sid algorithm 150 index 15x prefix-sid algorithm 160 index 16x ! address-family ipv6 unicast prefix-sid index 50x prefix-sid algorithm 140 index 54x prefix-sid algorithm 150 index 55x prefix-sid algorithm 160 index 56x !
Where x is the node number (PE1 is node 1 etc - see diagram).
PE1 is configured to steer traffic with BGP Autosteering. Basically, SR polcies steer prefixes with ext-comm colors 40, 50 and 60 (and destination PE4 - 10.1.1.4) into flex-algos 140, 150 and 160 respectively.
All 3 policies come up with no issues. Given that PE4 is the destination, policies 40, 50 and 60 apply SID stacks of 16144, 16154 and 16164 respecitvely (SRGB 16000). I'm testing forwarding them using colored VPNv4 routes (not shown).
Here is an example:
RP/0/RP0/CPU0:PE1#show segment-routing traffic-eng policy color 50
Sat Jul 12 23:13:09.122 UTC
SR-TE policy database
---------------------
Color: 50, End-point: 10.1.1.4
Name: srte_c_50_ep_10.1.1.4
Status:
Admin: up Operational: up for 00:23:34 (since Jul 12 22:49:34.514)
Candidate-paths:
Preference: 100 (configuration) (active)
Name: RED-LINKS
Requested BSID: dynamic
Constraints:
Prefix-SID Algorithm: 150
Protection Type: protected-preferred
Maximum SID Depth: 10
Dynamic (valid)
Metric Type: IGP, Path Accumulated Metric: 50
SID[0]: 16154 [Prefix-SID: 10.1.1.4, Algorithm: 150]
Attributes:
Binding SID: 24022
Forward Class: Not Configured
Steering labeled-services disabled: no
Steering BGP disabled: no
IPv6 caps enable: yes
Invalidation drop enabled: no
Max Install Standby Candidate Paths: 0
RP/0/RP0/CPU0:PE1#
Flex algo 140 and 160 work fine.
But flex-algo 150 is behaving weird.
It appears as though routers PE4, PE5, PE6, P1 and P2 are only installing some of the flex-algo indices:
RP/0/RP0/CPU0:PE6#show mpls forwarding | inc 1615 Sat Jul 12 23:03:47.993 UTC 16151 Pop SR Pfx (idx 151) Gi0/0/0/1 10.10.16.1 0 16155 Pop SR Pfx (idx 155) Gi0/0/0/0 10.10.56.5 0 16156 Aggregate SR Pfx (idx 156) default 0 16157 Pop SR Pfx (idx 157) Gi0/0/0/3 10.10.67.7 0 RP/0/RP0/CPU0:PE6#
Most importantly they've not installed 16154. All the other routers install them ok:
RP/0/RP0/CPU0:PE1#show mpls forwarding | inc 1615 Sat Jul 12 23:16:25.030 UTC 16151 Aggregate SR Pfx (idx 151) default 0 16152 16152 SR Pfx (idx 152) Gi0/0/0/0 10.10.16.6 0 16153 16153 SR Pfx (idx 153) Gi0/0/0/0 10.10.16.6 0 16154 16154 SR Pfx (idx 154) Gi0/0/0/0 10.10.16.6 0 16155 16155 SR Pfx (idx 155) Gi0/0/0/0 10.10.16.6 0 16156 Pop SR Pfx (idx 156) Gi0/0/0/0 10.10.16.6 0 16157 16157 SR Pfx (idx 157) Gi0/0/0/0 10.10.16.6 0 16158 16158 SR Pfx (idx 158) Gi0/0/0/0 10.10.16.6 0 24014 16154 SR TE: 3 [TE-INT] Gi0/0/0/0 10.10.16.6 0 RP/0/RP0/CPU0:PE1#
Most notably 16154 is missing which is lable for PE4s flex-algo 150.
I'm not sure why this is the case. From a config point of view I can't find anything wrong.
All devices are a part of topology 150. For example, PE6 has no entries for Algo 140 (include-all GREEN) but that makes sense as it wouldn't be a part of that topology.
PE4 is definitely advertising it's flex-algo indices in its LSPs. I've tried debugging but can't seem to figure it out.
Does anyone have any ideas? (I can provide more information or configs if needed).
