07-14-2021 05:44 PM
Hi Team,
Quick question which I have been unable to find a definitive answer for online.
I understand the concept of TLOC and OMP Route preference when selecting the destination TLOC for forwarding traffic, however I don't quite understand how the router makes a decision on source TLOC if there are multiple tunnel paths to the same destination TLOC.
Example
Branch router has two public TLOC's: public-internet and LTE. It is trying to reach destination 10.15.200.0/24, from the OMP output the chosen OMP route is via TLOC 172.18.255.2 public-internet. There are two active BFD sessions to this TLOC, one via public-internet and the other LTE. How can I determine what the chose source TLOC or interface is used, because there could be significant performance implications choosing one over the other. Also is there a way to influence this locally without using a central data policy?
BRANCH-ROUTER#show sdwan omp routes vpn 10 10.15.200.0/24
PATH ATTRIBUTE
FROM PEER ID LABEL STATUS TYPE TLOC IP COLOR ENCAP PREFERENCE
-----------------------------------------------------------------------------------------------------------
10.97.193.132 4407 1003 C,I,R installed 172.18.255.2 public-internet ipsec - (vSmart1)
10.97.195.132 4292 1003 C,R installed 172.18.255.2 public-internet ipsec - (vSmart2)
BRANCH-ROUTER#show sdwan bfd sessions
SYSTEM IP SITE ID STATE COLOR COLOR SOURCE IP IP PORT ENCAP MULTIPLIER INTERVAL(msec) UPTIME TRANSITIONS
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
172.18.255.2 11101 up lte public-internet 10.91.78.111 150.207.167.13 12406 ipsec 7 1000 0:21:03:52 0
172.18.255.2 11101 up biz-internet public-internet 192.168.1.11 150.207.167.13 12406 ipsec 7 1000 0:06:50:12 1
Appreciate any help.
Cheers!
Solved! Go to Solution.
07-15-2021 09:21 AM
Hi,
Normally, ECMP happens based on hashing result and result will be 50-50% traffic distribution, but you can use interface parameter "IPSec weight" to send more traffic over one interface. You should configure higher value for public-internet color, in your case.
Weight
The weight parameter can be used to send traffic over weighted tunnels, where a higher value sends more traffic to a tunnel compared to another. Weight is often used when the bandwidth of the TLOCs vary and you cannot perform ECMP over the links. Weight can be set from 1 to 255, with a default value of 1. Traffic distribution takes into account the remote TLOC weight as well as the local TLOC weight.
https://www.cisco.com/c/en/us/td/docs/solutions/CVD/SDWAN/cisco-sdwan-design-guide.html
HTH,
07-15-2021 09:21 AM
Hi,
Normally, ECMP happens based on hashing result and result will be 50-50% traffic distribution, but you can use interface parameter "IPSec weight" to send more traffic over one interface. You should configure higher value for public-internet color, in your case.
Weight
The weight parameter can be used to send traffic over weighted tunnels, where a higher value sends more traffic to a tunnel compared to another. Weight is often used when the bandwidth of the TLOCs vary and you cannot perform ECMP over the links. Weight can be set from 1 to 255, with a default value of 1. Traffic distribution takes into account the remote TLOC weight as well as the local TLOC weight.
https://www.cisco.com/c/en/us/td/docs/solutions/CVD/SDWAN/cisco-sdwan-design-guide.html
HTH,
07-18-2021 04:14 PM
Thanks Kanan thats great,
Cheers
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