Cisco Technology, Inc.

Sylvain Masse

David Delano Ward

Reshad Rahman

David P Toscano

Neil R Ketley

Jonathan Parker

Clarence Filsfils

Sami Boutros

Reshad A Rahman

In one embodiment, a plurality of links between a network node and another network node are configured as a link bundle. The network node establishes one or more standby bidirectional forwarding detection (BFD) sessions. Each standby BFD session is associated with one or more links of the link bundle. The network node establishes an active BFD session. The active BFD session is associated with one or more links of the link bundle. In response to non-receipt of returned BFD messages for the active BFD session, one or more new active BFD sessions are selected from the one or more standby BFD sessions. In response to non-receipt of returned BFD messages for the one or more new active BFD sessions, it is determined that the link bundle has failed.

Technique for efficiently and dynamically maintaining bidirectional forwarding detection on a bundle of links

In one embodiment, a local network device transmits a connectivity verification protocol control message over a link to a remote network device to attempt to establish a connectivity verification protocol session with the remote network device. In response to non-receipt of a returned connectivity verification protocol control message from the remote network device, the local network device determines that there is an inability to establish a connectivity verification protocol session with the remote network device. The local network device then sends a connectivity verification protocol echo message over the link to the remote network device without establishment of a connectivity verification protocol session. The echo message is sent using a forwarding protocol. In response to receipt of a reply to the connectivity verification protocol echo message from the remote network device, the local network device determines that the forwarding protocol is functioning and uses the link to forward data traffic to the remote network device.

Distinguishing between connectivity verification availability and forwarding protocol functionality in a computer network

In one embodiment, a connectivity verification protocol (CVP) session for a particular virtual interface (VI) may operate on a particular group of two or more line cards (LCs) on a network device. The group of LCs may then transmit CVP session packets, at a reduced rate that is sufficient to maintain the CVP session based on a negotiated CVP full rate, onto the particular VI through ingress path processing on the network device. Ingress path processing, in particular, takes transmitted CVP session packets and egresses them onto an appropriate LC of the network device currently responsible for the VI egress. Also, in response to receiving CVP session packets for the VI on an LC of the network device currently responsible for the VI ingress, the receiving LC may forward the received CVP session packets to the particular corresponding group of LCs, which may then process the received CVP session packets.

Distributed connectivity verification protocol redundancy

A technique efficiently and dynamically maintains bidirectional forwarding detection (BFD) on a bundle of links in a computer network. According to the novel technique, one or more 'standby' BFD sessions may be established on one or more corresponding line cards (LCs), the LCs having one or more links of the bundle (bundle links). Once established, one of the standby BFD sessions may be selected as an 'active' BFD session based on activity of one of the bundle links of the corresponding LC. Also, BFD messages may be transmitted from one of the bundle links of the active BFD session, e.g., the link receiving BFD messages. In response to inactivity of the transmitting link (e.g., failure, removal, etc.), the active BFD session may switch to another available active bundle link, and if no other active bundle links are available to the active BFD session, one of the standby BFD sessions is selected as the new active BFD session. In the event no other standby BFD sessions exist, the link bundle is determined to have failed.

In one embodiment, a local network device may determine an inability to establish a connectivity verification protocol (e.g., Bidirectional Forwarding Detection, 'BFD') session to a remote network device, such as from unreturned control messages. In response, the local network device may send at least one connectivity verification protocol echo message to the remote network device destined to be returned to the local network device and forwarded using a forwarding protocol. In response to receiving or not receiving the echo message, the local network device may thus determine whether the forwarding protocol is functioning between the local and remote network devices. In this manner, the local network device may determine whether an inability to establish a connectivity verification protocol session is due to an inability to forward packets between the devices, or due to the connectivity verification protocol not working (or not being configured) on the remote network device.

Growing community of inventors

Gatineau, Canada

Sylvain Masse