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Segment Routing for fate sharing

‎06-08-2019 09:23 AM

Dear Expert,

 

I met a problem. When you configure the fat sharing of an SR, the fate sharing takes effect when the ISIS interface of the primary path is modified to point-to-point. If it is a LAN interface type, it does not take effect.

 

top.png

Route from R1 to R3:

 

R1 configuration:

 

[edit]
jcluser@R1# show protocols isis | display set 
Jun 08 16:17:58
set protocols isis reference-bandwidth 1000g
set protocols isis backup-spf-options use-post-convergence-lfa maximum-backup-paths 2
set protocols isis backup-spf-options use-source-packet-routing
set protocols isis source-packet-routing srgb start-label 1000
set protocols isis source-packet-routing srgb index-range 9000
set protocols isis source-packet-routing node-segment ipv4-index 401
set protocols isis source-packet-routing node-segment ipv6-index 601
set protocols isis level 2 wide-metrics-only
set protocols isis interface ge-0/0/2.0 level 2 post-convergence-lfa node-protection cost 16777214
set protocols isis interface ge-0/0/2.0 level 2 post-convergence-lfa fate-sharing-protection
set protocols isis interface ge-0/0/2.0 level 2 metric 4000
set protocols isis interface all level 1 disable
set protocols isis interface all level 2 post-convergence-lfa node-protection cost 16777214
set protocols isis interface all level 2 post-convergence-lfa fate-sharing-protection

[edit]
jcluser@R1# show routing-options | display set 
Jun 08 16:18:05
set routing-options static route 0.0.0.0/0 next-hop 100.123.0.1
set routing-options autonomous-system 100
set routing-options forwarding-table export load
set routing-options fate-sharing group fs-test cost 65535
set routing-options fate-sharing group fs-test use-for-post-convergence-lfa
set routing-options fate-sharing group fs-test from 10.0.0.6 to 10.0.0.7
set routing-options fate-sharing group fs-test from 10.0.0.22 to 10.0.0.23

When the interface type of R1 and R3 is LAN:

[edit]
jcluser@R1# run show isis adjacency R3 extensive 
Jun 08 16:04:10
R3
  Interface: ge-0/0/2.0, Level: 2, State: Up, Expires in 21 secs
  Priority: 64, Up/Down transitions: 1, Last transition: 00:00:05 ago
  Circuit type: 3, Speaks: IP, IPv6, MAC address: 0:50:56:a2:25:5e
  Topologies: Unicast
  Restart capable: Yes, Adjacency advertisement: Advertise
  LAN id: R1.03, IP addresses: 10.0.0.23
  IPv6 addresses: fe80::250:56ff:fea2:255e
  Level 2 IPv4 Adj-SID: 28
  Level 2 IPv6 Adj-SID: 29
  State: Up

[edit]
jcluser@R1# run show isis interface ge-0/0/2.0 extensive 
Jun 08 16:04:15
IS-IS interface database:
ge-0/0/2.0
  Index: 334, State: 0x6, Circuit id: 0x3, Circuit type: 3
  LSP interval: 100 ms, CSNP interval: 10 s, Loose Hello padding, IIH max size: 1492
  Adjacency advertisement: Advertise, Layer2-map: Disabled
  Interface Group Holddown Delay: 20 s, remaining: 0 s
  Level 1
    Adjacencies: 0, Priority: 64, Metric: 63
    Hello Interval: 9.000 s, Hold Time: 27 s
  Level 2
    Adjacencies: 1, Priority: 64, Metric: 4000
    Hello Interval: 3.000 s, Hold Time: 9 s
    Designated Router: R1.03 (us)
    Post convergence Protection:Enabled, Fate sharing: Yes, Srlg: No, Node cost: 16777214



[edit protocols isis]
jcluser@R3# run show isis adjacency R1 extensive 
R1
  Interface: ge-0/0/2.0, Level: 2, State: Up, Expires in 7 secs
  Priority: 64, Up/Down transitions: 1, Last transition: 00:00:27 ago
  Circuit type: 2, Speaks: IP, IPv6, MAC address: 0:50:56:a2:52:8e
  Topologies: Unicast
  Restart capable: Yes, Adjacency advertisement: Advertise
  LAN id: R1.03, IP addresses: 10.0.0.22
  IPv6 addresses: fe80::250:56ff:fea2:528e
  Level 2 IPv4 Adj-SID: 24
  Level 2 IPv6 Adj-SID: 25
  State: Up

[edit protocols isis]
jcluser@R3# run show isis interface extensive ge-0/0/2.0  
IS-IS interface database:
ge-0/0/2.0
  Index: 334, State: 0x6, Circuit id: 0x1, Circuit type: 2
  LSP interval: 100 ms, CSNP interval: 10 s, Loose Hello padding, IIH max size: 1492
  Adjacency advertisement: Advertise, Layer2-map: Disabled
  Interface Group Holddown Delay: 20 s, remaining: 0 s
  Level 1
    Adjacencies: 0, Priority: 64, Metric: 63
    Disabled
  Level 2
    Adjacencies: 1, Priority: 64, Metric: 4000
    Hello Interval: 9.000 s, Hold Time: 27 s
    Designated Router: R1.03 (not us)

[edit]
jcluser@R1# run show route 192.168.0.3/32 table inet.3 
Jun 08 16:05:00

inet.3: 8 destinations, 8 routes (8 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

192.168.0.3/32     *[L-ISIS/14] 00:00:55, metric 4000
                    > to 10.0.0.23 via ge-0/0/2.0
                      to 10.0.0.3 via ge-0/0/0.0, Push 1403, Push 1407(top)
                      to 10.0.0.1 via ge-0/0/1.0, Push 1403, Push 1407(top)

When the interface types of R1 and R3 are point-to-point:

 

jcluser@R1# run show isis interface ge-0/0/2.0 extensive 
Jun 08 16:02:05
IS-IS interface database:
ge-0/0/2.0
  Index: 334, State: 0x6, Circuit id: 0x1, Circuit type: 3
  LSP interval: 100 ms, CSNP interval: 5 s, Loose Hello padding, IIH max size: 1492
  Adjacency advertisement: Advertise, Layer2-map: Disabled
  Interface Group Holddown Delay: 20 s, remaining: 0 s
  Level 1
    Adjacencies: 0, Priority: 64, Metric: 63
    Hello Interval: 9.000 s, Hold Time: 27 s
  Level 2
    Adjacencies: 1, Priority: 64, Metric: 4000
    Hello Interval: 9.000 s, Hold Time: 27 s
    Post convergence Protection:Enabled, Fate sharing: Yes, Srlg: No, Node cost: 16777214

[edit protocols isis]
jcluser@R1# run show isis adjacency R3 extensive 
Jun 08 16:02:24
R3
  Interface: ge-0/0/2.0, Level: 2, State: Up, Expires in 24 secs
  Priority: 0, Up/Down transitions: 1, Last transition: 00:01:48 ago
  Circuit type: 3, Speaks: IP, IPv6
  Topologies: Unicast
  Restart capable: Yes, Adjacency advertisement: Advertise
  IP addresses: 10.0.0.23
  IPv6 addresses: fe80::250:56ff:fea2:255e
  Level 2 IPv4 Adj-SID: 26
  Level 2 IPv6 Adj-SID: 27
  State: Up


[edit]
jcluser@R3# run show isis adjacency R1 extensive 
R1
  Interface: ge-0/0/2.0, Level: 2, State: Up, Expires in 26 secs
  Priority: 0, Up/Down transitions: 1, Last transition: 00:02:21 ago
  Circuit type: 2, Speaks: IP, IPv6
  Topologies: Unicast
  Restart capable: Yes, Adjacency advertisement: Advertise
  IP addresses: 10.0.0.22
  IPv6 addresses: fe80::250:56ff:fea2:528e
  Level 2 IPv4 Adj-SID: 22
  Level 2 IPv6 Adj-SID: 23
  State: Up

[edit]
jcluser@R3# run show isis interface ge-0/0/2.0 extensive 
IS-IS interface database:
ge-0/0/2.0
  Index: 334, State: 0x6, Circuit id: 0x1, Circuit type: 2
  LSP interval: 100 ms, CSNP interval: 5 s, Loose Hello padding, IIH max size: 1492
  Adjacency advertisement: Advertise, Layer2-map: Disabled
  Interface Group Holddown Delay: 20 s, remaining: 0 s
  Level 1
    Adjacencies: 0, Priority: 64, Metric: 63
    Disabled
  Level 2
    Adjacencies: 1, Priority: 64, Metric: 4000
    Hello Interval: 9.000 s, Hold Time: 27 s


[edit protocols isis]
jcluser@R1# run show route 192.168.0.9/32 table inet.3 
Jun 08 16:03:22

inet.3: 8 destinations, 8 routes (8 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

192.168.0.9/32     *[L-ISIS/14] 00:02:46, metric 7000
                    > to 10.0.0.23 via ge-0/0/2.0, Push 1409
                      to 10.0.0.1 via ge-0/0/1.0, Push 1409
					  
					  

The need for the experiment is to see that there is only one backup path in the routing table because there is a conflict with the Primary Path. But for now, I didn't find any more explanation. When the LAN interface, Fate Sharing does not seem to take effect.

 

Maybe this is a design issue, or my configuration problem. thank...

 

 

5 REPLIES 5
Highlighted
Junos

Re: Segment Routing for fate sharing

‎06-08-2019 02:25 PM
Hello, LAN interfaces are configured differently for fate-sharing ("to" clause is not necessary), see example at https://www.juniper.net/documentation/en_US/junos/topics/usage-guidelines/mpls-configuring-the-ingre... Please reconfigure, re-test and report back. HTH Thx Alex
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Highlighted
Junos

Re: Segment Routing for fate sharing

‎06-08-2019 08:11 PM
Hi Likang, Could you please check show route 192.168.0.3/32 table inet.3 in the second case when ISIS interface is point to point just to make sure that there is a difference after this modification , also check at R4 if there is another link -(R4-R6) link - is up and under ISIS maybe because of that path through ge-0/0/1 is still considered as it does not pass through R4-R5 link . --------------------------------- If this solves your problem, please mark this post as "Accepted Solution."
Regards,
A.A.
Highlighted
Junos

Re: Segment Routing for fate sharing

‎06-08-2019 08:44 PM

Dear Guys,

 

This reference link is for RSVP. I configured the LAN interface IP address and Router-id, but did not calculate Fate Sharing, it does not seem to take effect.

 

[edit routing-options fate-sharing group fs-test]
jcluser@R1# show | display set 
set routing-options fate-sharing group fs-test cost 65535
set routing-options fate-sharing group fs-test use-for-post-convergence-lfa
set routing-options fate-sharing group fs-test from 10.0.0.6
set routing-options fate-sharing group fs-test from 10.0.0.22

jcluser@R1# run show mpls fate-sharing 
Group fs-test {
  Cost 65535
  10.0.0.6
  10.0.0.22
}


inet.3: 8 destinations, 8 routes (8 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

192.168.0.3/32     *[L-ISIS/14] 00:03:18, metric 4000
                    > to 10.0.0.23 via ge-0/0/2.0
                      to 10.0.0.3 via ge-0/0/0.0, Push 1403, Push 1407(top)
                      to 10.0.0.1 via ge-0/0/1.0, Push 1403, Push 1407(top)
Highlighted
Junos

Re: Segment Routing for fate sharing

‎06-08-2019 08:56 PM

Dear guys,

 

The link between R4 and R6 is an interrupt. Let's take a look at the topology above.

 

I didn't see any difference for the type of interface modified to ISIS. I also showed it out on the top.

 

I did not find the information. But the answer may be like this: Fast Sharing's Backup Path can't share a common physical link with the primary path. The Primary Path interface type should be point-to-point. If the LAN is probably a shared link, there is no such thing. success.

Highlighted
Junos

Re: Segment Routing for fate sharing

‎06-09-2019 02:48 AM
Hi Likang, i see from the diagram that R4-R6 link is not there but just wanted to make sure that actual configuration matches it , also could you check R4-R5 link ISIS configuration ? is it point-to-point or LAN interface ? --------------------------- If this solves your problem, please mark this post as "Accepted Solution."
Regards,
A.A.
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