Hi Yagnesh,
I am sorry to be responding late - these were some busy days.
1) As per my knowledge we haven't enable wide metic on any router . R2 is Junos router and we need to add command for that. How you come to know it support wide metric ?
In your output of R2's LSP, R2 indicates an "IS-Extended" adjacency to R1, proving it is running wide metrics. An adjacency using narrow metrics would be denoted simply as "IS", not 'IS-Extended".
R1# show isis database R2.00-00 detail
Tag area_0041:
IS-IS Level-2 LSP R2.00-00
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
R2.00-00 0x00000188 0x0C92 882 0/0/0
Area Address: 39.250f.0000.4900.0001.00ae
NLPID: 0xCC 0x8E
Router ID: 10.214.253.11
IP Address: 10.214.253.11
Hostname: R2
Metric: 15 IS-Extended R1.00
Metric: 15 IP 172.16.16.32/30
Metric: 0 IP 10.214.253.11/32
Metric: 10 IP 172.29.128.0/26
If R2 is using wide metrics, R1 must be verified to use wide metrics as well, otherwise R1 and R2 will be IS-IS neighbors but their routing tables will remain empty.
2)Does it make any difference , we didn't enable this feature either , it's some GRE tunnel , how you cone to know R2 supports both
This question relates to the support of IPv4 and IPv6. Check the LSP output above again, specifically, the NLPID field. NLPID (Network Layer Protocol ID) is the set of Layer3 protocols supported by the router. 0xCC identifies IPv4, 0x8E identifies IPv6.
This LSP does not show for sure if R2 expects R1 to run IPv6 toward R2. However, if R2 was configured for both IPv4 and IPv6 on the tunnel toward R1, and R1 had no IPv6 activated on this tunnel, then these two routers would not even become IS-IS neighbors. According to your description, this is not the case.
I really suggest verifying the metric style on R1. Ideally, R1 should be configured with metric-style wide in the router isis section. The question is - does R1 have any other IS-IS neighbors besides R2? If so then the metric style on those neighbors would need to be changed as well.
Best regards,
Peter
