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Cisco Bug: CSCvs05464 - UI doesn't show correct path though XTC sends correct path When different SRGBs are used in diff ASs

Last Modified

Jan 13, 2020

Products (1)

  • Cisco Service Provider Network Automation Center

Known Affected Releases

1.1

Description (partial)

Symptom:
When different SRGBs are used in diff ASes, UI does not show correct path though XTC sends correct path:

-	I'm using cw-optima-1.1.0-1011-develop-191030.ova.

-	As shown in 1.jpg, path shown in UI is not correct.

-	XTC sends correct path. See XTC output mylspdump.txt attached.
root@172-29-104-132-master ~# kubectl exec -it robot-topo-svc-7966ffbcd6-srgsl bash
bash-5.0# curl ip.253:8080/lsp/subscribe/txt > mylspdump.txt
bash-5.0#vi mylspdump.txt
Symbolic-name: cfg_vicsrp101216_002_discr_5, LSP-ID: 1,
Source: 192.168.101.101 Destination: 192.168.101.216,
D:0, R:0, A:1 O:1, Sig.BW: 0, Act.BW: 0
Reported Path: (Metric 0)
Label 311007
Label 311006
Label 311005
Label 311011
Label 312002   <- XTC sends correct path info.
Label 312010
Label 312009
Label 312008
Label 312011
Label 312016

Notes from Jessica:
This is an explicit sid SR policy.  The way TopoSvc traverses the explicit sid is to determine whether it's a node prefix sid or a link adjacency sid with the corresponding SRGB range.  Hence, the first 4 hops were resolved without issues because they are in the same AS and the prefix sid falls inside SRGB range (311000-311999):
Label 311007
Label 311006
Label 311005
Label 311011
 
Now, the 5th hop is the one that causes issues because it's in another AS.  For this one we have the explicit sid as 312002, which falls outside of the SRGB range for hop #4.  TopoSvc will decide this to be an adjacency hop.  However, there is no such adj sid because it's actually a prefix sid in the other AS.   
 
Hi Max,
 
How do we resolve this issue?  The node prefix sid is global within the same AS.  The adj sid is only locally significant.  So for hop #4 which is a node, it's hard to determine whether the next hop is a prefix sid or an adjacency sid.  Can you please advise?

Conditions:
Condition:
When different SRGBs are used in diff ASes...
What happens:
... UI does not show correct path though XTC sends correct path.
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