[SDWAN] Overlay Management Protocol (OMP) - Part 3 (English)

Continuing with OMP routes,

Like BGP, OMP route (vRoute) contains many other attributes:

• TLOC next hop (mentioned in the previous article)
• VPN
• Originator
• Site ID
• Preference

Each OMP route associates to a certain VPN in the SDWAN network, to be scalable as the VRF in the MPLS network.

By default, the vRoutes in each VPN are separated from the other VPN's route tables in the network.

Each OMP route carries a VPN-ID corresponding to the prefix during OMP update progress. When cEdges receives OMP updates from vSmart, it allocates vRoute to the corresponding VPN and install the prefix to the route table.

OMP collects the routes which are learned from the local network, then updates to OMP peers (vSmarts) as output below, vEdge11 will update to vSmart (9.9.9.30).

from vEdge11#

vEdge11# show omp peers

R -> routes received
I -> routes installed
S -> routes sent


? ? ? ? ? ? ?  ? DOMAIN? ?OVERLAY? SITE
PEER? ? ? ?TYPE? ? ID? ? ? ID? ? ? ?ID? ?STATE? UPTIME?    R/I/S
---------------------------------------------------------------
9.9.9.30? ?vsmart? 1? ? ? ?1? ? ? ? 99? ? up? ?0:10:16:52? ?2/2/2        

from cEdge41#

cEdge41#show sdwan omp peers

R -> routes received
I -> routes installed
S -> routes sent


? ? ? ? ? ? ? ? ?DOMAIN? OVERLAY? SITE
PEER ?   ?TYPE? ?ID? ? ?ID? ? ? ? ID? ? STATE? UPTIME?     R/I/S
---------------------------------------------------------------
9.9.9.30?vsmart? 1? ? ? 1? ? ? ? ?99? ? up? ? 6:03:33:18? ? 1/1/2        

from vSmart#

vSmart1# show omp peers

R -> routes received
I -> routes installed
S -> routes sent


? ? ? ? ? ? ? ?   DOMAIN? OVERLAY?SITE
PEER? ?    TYPE? ?ID? ? ? ID? ? ? ID? ? STATE? UPTIME? ?   R/I/S
--------------------------------------------------------------
1.1.1.11? vedge? ?1? ? ? ?1? ? ? ?10? ?  up? ?0:10:20:15?  2/0/2
1.1.1.40? vedge? ?1? ? ? ?1? ? ? ?40? ?  up? ?6:08:41:00? ?2/0/1        

As above output from vSmart, there are 2 OMP peers on vSmart , cEdge11 and cEdge41, which vSmart will receive and send updates to.

As Figure 1, let's verify routing information by checking the omp vpn 100 routing table of each cEdges.

from vEdge11#

vEdge11# show omp routes vpn 100


---------------------------------------------------
omp route entries for vpn 100 route 192.168.10.0/24
---------------------------------------------------
? ? ? ? ? ? RECEIVED FROM:
peer? ? ? ? ? ? 0.0.0.0
path-id? ? ? ? ?69
label? ? ? ? ? ?1002
status? ? ? ? ? C,Red,R
loss-reason? ? ?not set
lost-to-peer? ? not set
lost-to-path-id not set
? ? Attributes:
? ? ?originator? ? ? ?1.1.1.11
? ? ?type? ? ? ? ? ? ?installed
? ? ?tloc? ? ? ? ? ? ?1.1.1.11, public-internet, ipsec
? ? ?ultimate-tloc? ? not set
? ? ?domain-id? ? ? ? not set
? ? ?overlay-id? ? ? ? 1
? ? ?site-id? ? ? ? ? 10
? ? ?preference? ? ? ?not set
? ? ?tag? ? ? ? ? ? ? not set
? ? ?origin-proto? ? ?connected
? ? ?origin-metric? ? 0
? ? ?as-path? ? ? ? ? not set
? ? ?unknown-attr-len not set

? ? ? ? ? ? ADVERTISED TO:
peer? ? 9.9.9.30


---------------------------------------------------
omp route entries for vpn 100 route 192.168.40.0/24
---------------------------------------------------

? ? ? ? ? ? RECEIVED FROM:

peer? ? ? ? ? ? 9.9.9.30
path-id? ? ? ? ?291
label? ? ? ? ? ?1002
status? ? ? ? ? C,I,R
loss-reason? ? ?not set
lost-to-peer? ? not set
lost-to-path-id not set
? ? Attributes:
? ? ?originator? ? ? ?1.1.1.40
? ? ?type? ? ? ? ? ? ?installed
? ? ?tloc? ? ? ? ? ? ?1.1.1.40, public-internet, ipsec
? ? ?ultimate-tloc? ? not set
? ? ?domain-id? ? ? ? not set
? ? ?overlay-id? ? ? ? 1
? ? ?site-id? ? ? ? ? 40
? ? ?preference? ? ? ?not set
? ? ?tag? ? ? ? ? ? ? not set
? ? ?origin-proto? ? ?connected
? ? ?origin-metric? ? 0
? ? ?as-path? ? ? ? ? not set
? ? ?unknown-attr-len not set        

192.168.10.0/24 is a directly connected network belonging to the internal network of vEdge11#, so look at Attributes originator above, it is the system-ip of vEdge11#, 1.1.1.11. Also, at the ADVERTISED TO: peer 9.9.9.30 (vSmart system-ip), it shows this prefix has been distributed to vSmart mentioned above.

Regarding the status of prefix 192.168.10.0/24 as output above, (C, Red, R):

• C: choosen, it means the prefix chosen as the best path
• Red: redistributed, it means the prefix is redistributed from the IGP protocol, connected, ... into OMP. (In this case, look at the origin-proto, the value is connected, it shows the origin protocol for this prefix is directly connected)
• R: resolved, it is tloc-nexthop available and reachability. (valid)

192.168.40.0/24 is the network prefix that vEdge11 received from vSmart (9.9.9.30), and you can see the originator is 1.1.1.40, the system-ip of cEdge41. Based on it, you can know this prefix comes from the service side of cEdge41.

In addition, the prefix 192.168.40.0/24 contains other attributes such as site-id 40 that tells us that cEdge41's site is 40, and tloc information as mentioned in the previous article. (system-ip, color, encap).

Regarding the status of prefix 192.168.40.0/24 as output above, (C, I, R):

• I: installed, it means the prefix has been installed into the routing table.

Similarly, on cEdge41, people can refer to the output below.

from cEdge41#

cEdge41#show sdwan omp routes vpn 100 detail


---------------------------------------------------
omp route entries for vpn 100 route 192.168.10.0/24
---------------------------------------------------

? ? ? ? ? ? RECEIVED FROM:

peer? ? ? ? ? ? 9.9.9.30
path-id? ? ? ? ?221
label? ? ? ? ? ?1002
status? ? ? ? ? C,I,R
loss-reason? ? ?not set
lost-to-peer? ? not set
lost-to-path-id not set
? ? Attributes:
? ? ?originator? ? ? ?1.1.1.11
? ? ?type? ? ? ? ? ? ?installed
? ? ?tloc? ? ? ? ? ? ?1.1.1.11, public-internet, ipsec
? ? ?ultimate-tloc? ? not set
? ? ?domain-id? ? ? ? not set
? ? ?overlay-id? ? ? ? 1
? ? ?site-id? ? ? ? ? 10
? ? ?preference? ? ? ?not set
? ? ?tag? ? ? ? ? ? ? not set
     origin-proto? ? ?connected
? ? ?origin-metric? ? 0
? ? ?as-path? ? ? ? ? not set
? ? ?community? ? ? ? not set
? ? ?unknown-attr-len not set


---------------------------------------------------
omp route entries for vpn 100 route 192.168.40.0/24
---------------------------------------------------

? ? ? ? ? ? RECEIVED FROM:

peer? ? ? ? ? ? 0.0.0.0
path-id? ? ? ? ?69
label? ? ? ? ? ?1002
status? ? ? ? ? C,Red,R
loss-reason? ? ?not set
lost-to-peer? ? not set
lost-to-path-id not set
? ? Attributes:
? ? ?originator? ? ? ?1.1.1.40
? ? ?type? ? ? ? ? ? ?installed
? ? ?tloc? ? ? ? ? ? ?1.1.1.40, public-internet, ipsec
? ? ?ultimate-tloc? ? not set
? ? ?domain-id? ? ? ? not set
? ? ?overlay-id? ? ? ? 1
? ? ?site-id? ? ? ? ? 40
? ? ?preference? ? ? ?not set
? ? ?tag? ? ? ? ? ? ? not set
? ? ?origin-proto? ? ?connected
? ? ?origin-metric? ? 0
? ? ?as-path? ? ? ? ? not set
? ? ?community? ? ? ? not set
? ? ?unknown-attr-len not set

? ? ? ? ? ? ADVERTISED TO:

peer? ? 9.9.9.30        

Another very important attribute in OMP routes is omp preference, which is used in the process of selecting the best path if there is more than one path to the destination prefix.?

• With a larger omp preference value, higher priority the prefix gets.

In these examples above, I have not set the omp preference, so the value is "not set". It will be introduced in the best path selection detail articles.

See you in the next post about Service Routes.