IP PRECEDENCE 6 FOR ROUTING PROTOCOL

This table lists the values of the precedence bits:

Number	Bit Value	Name
0	000	Routine
1	001	Priority
2	010	Immediate
3	011	Flash
4	100	Flash Override
5	101	CRITIC/ECP
6	110	Internetwork Control
7	111	Network Control

   Cisco IOS assigns an IP precedence of 6 to routing protocol packets on the control plane. As noted by RFC 791, "The Internetwork Control designation is intended for use by gateway control originators only." Specifically, Cisco IOS marks these IP-based control packets: Open Shortest Path First (OSPF), Routing Information Protocol (RIP), Enhanced Interior Gateway Routing Protocol (EIGRP) hellos, and keepalives. Telnet packets to and from the router also receive an IP precedence value of 6. The assigned value remains with the packets when the output interface transmits them into the network.