Configuring OMP & Its attributes
Configuring OMP & Its attributes
OMP protocol is enabled by default and OMP graceful restart is a process which enables OMP peers to continue sending data traffic even though one of the Peer become unavailable for some unknown reason.
Let’s suppose, if vSmart is unavailable, vEdge will continue sending data traffic based on last known OMP routing information received from vSmart controller , likewise , if vEdge is unknown , the vSmart will use its last known routing information it received .
OMP graceful restart is enabled by default on vEdge and vSmart and its default restart time is 12 hrs. This timer indicates that how long the devices will cache the information. When timer expires, the cache routes are no longer valid. As soon as it is enabled, vEdge and vSmart will cache the OMP information received from their peer. This information is OMP routes, TLOC routes, Service Routes, IPSEC SA parameters, centralized data policies.
When any device between vEdge and vSmart is unavailable, they periodically check whether vSmart is available again or not, when they come up, they re-establish the connection and then flush their old routing and other information and cache the latest information received.
To modify the default timer:
Timer range is 1 to 604800 seconds (7 days)
It is recommended to enable the same timer in all vEdge and vSmart devices.
To Disable OMP graceful start:
Advertise Routes to OMP
By default, vEdge router advertises connected, static, OSPF (intra area and inter area) routes to OMP and router does not advertise BGP and OSPF external routes to OMP.
To advertise and configure so that vEdge advertise those routes to OMP:
To enable vEdge to advertise routes to OMP for specific VPN
if you want to advertise specific network instead of advertising all routes use Network command and specify particular prefix.
If aggregation is also used then by default all aggregated and specific routes are advertised, if the requirement is to only advertise aggregated routes, use aggregate-only option.
OMP advertise command will advertise all routes across all VPN, and vpn omp advertise command will advertise routes for that VPN only.
By default, when BGP advertises routes into OMP, BGP advertises each prefix's metric. BGP can also advertise the prefix's AS path when you configure below command.
After you configure the above command, the vEdge router will send the AS path information to those router which are behind this vEdge router that is service side network and running BGP and also it receives the AS path information from them.
Once BGP route are redistributed to OMP, AS path information is included in routes, using this command avoids the BG running routing loops.
If in any network , other Overlay ( Viptela ) and underlay ( MPLS ) network are present , that means when any vEdge is connected by MPLS and Viptela Overlay network , it is possible to assign AS number to OMP itself if vEdge router running BGP and this AS number will be included in BGP routing updates.
Configure the Number of Advertised Routes
As soon as any vEdge learns the network, it advertise to vSmart and vSmart further advertises to rest of vEdge in Overlay network. These routes are advertised as tuple (routes and TLOC associated with routes)
A vEdge route can have six different interface thus has 6 different TLOC. By default vEdge router and vSmart controller advertises up to four equal cost route value for same route, but it is possible to configure and advertise from 1 to 16 route–TLOC tuples for the same route:
If the limit is lower than the number of route–TLOC tuples, the vEdge router or vSmart controller advertises the best routes.
Configure the Number of Installed OMP Paths
By default , vEdge router installs a maximum of four unique OMP paths in to its route table , it can be modified by
Configure the OMP Hold Time
This hold down time determine, how long a device should wait before closing OMP connection to a peer. If by default peer does not receive three consecutive keep alive message with in hold time , it will peer down the OMP connection.
Default OMP hold down timer is : 60 sec and The keepalive timer is one-third the hold time and is not configurable.
Range is 1 to 65535 sec.
Configure the OMP Update Advertisement Interval
By default, OMP sends Update packets once per second. To modify this interval: