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 <[email protected]> 
Sent: Friday, September 18, 2020 11:53 AM
To: Aaron <[email protected]>
Cc: [email protected]
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 <[email protected] <mailto:[email protected]> > 
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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