Patent ID: 7920481

Claim:
In a network comprising a plurality of nodes including a first node and a second node, a subnetwork comprising a plurality of linked routers, and a third node connected to the plurality of nodes via the subnetwork, a method comprising: receiving, at a first router linked to the plurality of nodes, a first maximum transmission unit (MTU) error message from another router of the subnetwork, the first MTU error message including data representative of a first link MTU of a first link of the subnetwork that is in a first communication path between the plurality of nodes and the third node; generating, at the first router, a first MTU change message in response to receiving the first MTU error message, the first MTU change message including data representative of the first link MTU; transmitting, from the first router, the first MTU change message to the plurality of nodes; establishing a second communication path between the plurality of nodes and the third node via the subnetwork in response to a failure of a link of the first communication path, the second communication path having a second link with a second link MTU that is lower than the first link MTU represented by the first MTU error message; transmitting a data packet having a size equal to the first link MTU from the first node to the subnetwork; transmitting, from a second router of the plurality of linked routers, a second MTU error message to the first router in response to determining at the second router that the size of the data packet exceeds the second link MTU, the second MTU error message including data representative of the second link MTU; generating, at the first router, a second MTU change message in response to receiving the second MTU error message, the second MTU change message including data representative of the second link MTU; and transmitting, from the first router, the second MTU change message to the plurality of nodes.