Supported Features; Protocols And Standards - HP 5130 EI Series Configuration Manual

Control packets—Encapsulated into UDP packets with port number 3784 for single-hop detection
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or port number 4784 for multihop detection.
Echo packet mode
The local end of the link sends echo packets to establish BFD sessions and monitor link status. The peer
end does not establish BFD sessions and only forwards the packets back to the originating end.
In echo packet mode, BFD supports only single-hop detection and the BFD session is independent of the
operating mode.
Control packet mode
Both ends of the link exchange BFD control packets to monitor link status.
Before a BFD session is established, BFD has two operating modes—active and passive.
Active mode—BFD actively sends BFD control packets regardless of whether any BFD control
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packet is received from the peer.
• Passive mode—BFD does not send control packets until a BFD control packet is received from the
peer.
At least one end must operate in active mode for a BFD session to be established.
After a BFD session is established, the two ends can operate in the following BFD operating modes:
Asynchronous mode—The device periodically sends BFD control packets. The device considers that
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the session is down if it does not receive any BFD control packets within a specific interval.
Demand mode—The device periodically sends BFD control packets. If the peer end is operating in
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Asynchronous mode (default), the peer end stops sending BFD control packets. If the peer end is
operating in Demand mode, both ends stop sending BFD control packets. When the connectivity to
another system needs to be verified explicitly, a system sends several BFD control packets that have
the Poll (P) bit set at the negotiated transmit interval. If no response is received within the detection
interval, the session is considered down. If the connectivity is found to be up, no more BFD control
packets are sent until the next command is issued.
In addition, both ends of the link can exchange BFD control packets to establish and maintain BFD
sessions, and one end of the link sends echo packets to monitor link status.

Supported features

Static routing. For more information, see Layer 3—IP Routing Configuration Guide.
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IPv6 static routing. For more information, see Layer 3—IP Routing Configuration Guide.
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RIP. For more information, see Layer 3—IP Routing Configuration Guide.
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Track. For more information, see
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IP fast reroute (FRR). IP FRR is supported by RIP and static routing. For more information, see Layer
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3—IP Routing Configuration Guide.

Protocols and standards

RFC 5880, Bidirectional Forwarding Detection (BFD)
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• RFC 5881, Bidirectional Forwarding Detection (BFD) for IPv4 and IPv6 (Single Hop)
RFC 5882, Generic Application of Bidirectional Forwarding Detection (BFD)
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• RFC 5883, Bidirectional Forwarding Detection (BFD) for Multihop Paths
"Configuring Track."
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