[c-nsp] SR-TE
aaron1 at gvtc.com
aaron1 at gvtc.com
Fri Sep 18 17:10:06 EDT 2020
Yes L3VPN between r20 and r22… redistribute connected /30’s for both sides. Pretty straightforward l3vpn. R10 and r30 (ce’s) can ping each other. The l3vpn over SR-MPLS is working fine. It’s the SR-TE that I am now trying to make work that isn’t quite there yet. At this point I would just like to at least get a one-sided srte tunnel working r20----->r22 for now
I did move my lab over to a Xrv9k 7.0.2 and now seems to be doing better but not quite there yet. I see an sr-te interface now and in the LFIB. But I don’t see this in the routing table just yet. (like I am accustomed to seeing with autoroute announce with MPLS-TE/RSVP-TE)
I’ll have to look at what you sent me to see if I can get this in the routing table since it seems that’s why I’m not steering traffic into it yet…. But I could be wrong.
I’m unsure if I need to do bgp tweaks as Phil has suggested and I’ve also read. I’m wondering if I just need to someone make the bgp next hop for the L3VPN to be more attractively reachable via the SRTE Path vice the IGP least cost path.
RP/0/RP0/CPU0:r20#sh mpls for
Fri Sep 18 16:01:08.827 CDT
Local Outgoing Prefix Outgoing Next Hop Bytes
Label Label or ID Interface Switched
------ ----------- ------------------ ------------ --------------- ------------
100 Pop No ID srte_c_1_ep_ point2point 0
16021 Pop SR Pfx (idx 21) Gi0/0/0/0 10.20.1.2 0
16022 16022 SR Pfx (idx 22) Gi0/0/0/0 10.20.1.2 334015
16023 16023 SR Pfx (idx 23) Gi0/0/0/1 10.20.1.21 0
16024 Pop SR Pfx (idx 24) Gi0/0/0/1 10.20.1.21 0
24000 Pop SR Adj (idx 0) Gi0/0/0/0 10.20.1.2 0
24001 Aggregate one: Per-VRF Aggr[V] \
one 1669272
24002 Pop SR Adj (idx 0) Gi0/0/0/1 10.20.1.21 0
24009 24002 SR TE: 6 [TE-INT] Gi0/0/0/1 10.20.1.21 0 <<<---------------
RP/0/RP0/CPU0:r20#show ip int br
Fri Sep 18 16:03:25.282 CDT
Interface IP-Address Status Protocol Vrf-Name
srte_c_1_ep_10.20.0.22 10.20.0.20 Up Up default <<<-------------------
Loopback0 10.20.0.20 Up Up default
MgmtEth0/RP0/CPU0/0 unassigned Up Up default
GigabitEthernet0/0/0/0 10.20.1.1 Up Up default
GigabitEthernet0/0/0/1 10.20.1.22 Up Up default
GigabitEthernet0/0/0/2 1.0.0.1 Up Up one
GigabitEthernet0/0/0/3 unassigned Up Up default
Show interfaces…..
srte_c_1_ep_10.20.0.22 is up, line protocol is up
Interface state transitions: 1
Hardware is Tunnel-TE
Internet address is 10.20.0.20/32
MTU 1500 bytes, BW 0 Kbit
reliability 255/255, txload Unknown, rxload Unknown
Encapsulation TUNNEL, loopback not set,
Last link flapped 02:23:10
Last input never, output never
Last clearing of "show interface" counters never
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 total input drops
Unknown drops for unrecognized upper-level protocol
Received Unknown broadcast packets, Unknown multicast packets
0 packets output, 0 bytes, 0 total output drops
Output Unknown broadcast packets, Unknown multicast packets
*** not in the routing table yet…
RP/0/RP0/CPU0:r20#sh route | be Gate
Fri Sep 18 16:06:07.810 CDT
Gateway of last resort is not set
L 10.20.0.20/32 is directly connected, 04:51:44, Loopback0
O 10.20.0.21/32 [110/2] via 10.20.1.2, 04:50:47, GigabitEthernet0/0/0/0
O 10.20.0.22/32 [110/3] via 10.20.1.2, 02:49:18, GigabitEthernet0/0/0/0
O 10.20.0.23/32 [110/3] via 10.20.1.21, 04:40:42, GigabitEthernet0/0/0/1
O 10.20.0.24/32 [110/2] via 10.20.1.21, 04:40:48, GigabitEthernet0/0/0/1
C 10.20.1.0/30 is directly connected, 04:51:44, GigabitEthernet0/0/0/0
L 10.20.1.1/32 is directly connected, 04:51:44, GigabitEthernet0/0/0/0
O 10.20.1.4/30 [110/2] via 10.20.1.2, 02:49:18, GigabitEthernet0/0/0/0
O 10.20.1.8/30 [110/3] via 10.20.1.2, 02:49:18, GigabitEthernet0/0/0/0
[110/3] via 10.20.1.21, 02:49:18, GigabitEthernet0/0/0/1
C 10.20.1.20/30 is directly connected, 04:51:44, GigabitEthernet0/0/0/1
L 10.20.1.22/32 is directly connected, 04:51:44, GigabitEthernet0/0/0/1
O 10.20.1.24/30 [110/2] via 10.20.1.21, 04:40:47, GigabitEthernet0/0/0/1
L 127.0.0.0/8 [0/0] via 0.0.0.0, 04:51:45
From: dip <diptanshu.singh at gmail.com>
Sent: Friday, September 18, 2020 11:53 AM
To: Aaron <aaron1 at gvtc.com>
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] SR-TE
Yeah, there are certainly few ways to configure SR-TE. In your example, How's R10 learning R20 Prefixes? I am assuming that's BGP between PE-CE's (Is it L3VPN's ??) and PE's are doing next-hop-self. So the R30 prefix is learned via BGP at R20 with R22 as the next-hop making. You have a tunnel from R20--> R22 (inferring based on the loopback IP).
I don't have access to a box to check what cli options are available or not but you can try few things
1) Static route mapping to the destination. Page 59
2) see if there is an auto-route announce option available under policy for IGP to use the routes via the tunnel destination.
Take a look at this config guide which seems relatively more comprehensive
https://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k-r6-6/segment-routing/configuration/guide/b-segment-routing-cg-asr9000-66x/b-segment-routing-cg-asr9000-66x_chapter_01000.pdf
Page5:
https://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k-r6-2/segment-routing/configuration/guide/b-segment-routing-cg-asr9000-62x/b-seg-routing-cg-asr9000-62x_chapter_01000.pdf
Thanks
Dip
On Fri, Sep 18, 2020 at 8:59 AM <aaron1 at gvtc.com <mailto:aaron1 at gvtc.com> > wrote:
Thanks dip, but a bit confused at this point since I thought SRTE didn’t need tunnel interface at the Head End LSR, and that a policy was what steered traffic into an SRTE Path.
But, I do see some web sites that mention it both ways… using tunnel interface or using an sr-te policy… So I don’t know why they difference. Is it that some version of XR did it with only a tunnel interface and other versions of XR did it with policy? (heck I even see some that show a static route calling a explicit path option! IOS-XE website)
https://www.lacnic.net/innovaportal/file/4016/1/sr_srte_pce-hands-on.pdf
slide number 28 shows SR-TE policy
https://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/segment-routing/configuration/guide/b-seg-routing-cg-asr9k/b-seg-routing-cg-asr9k_chapter_0100.html
shows sr-te on tunnel interface
I was trying on XR 6.3.1 XRv using OSPF as IGP
I have a different virtual lab environment where I have XR 7.0.2 XRv9k and I am going to try it there with IS-IS as IGP
I’ll take any advice from anyone that has info on this.
-Aaron
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