Default Routing Engine Protocol Queue Assignments
Table 1 lists (in alphabetical order) how Routing Engine-sourced traffic is mapped to output queues. The follow caveats apply to Table 1:
- For all packets sent to queue 3 over a VLAN-tagged interface, the software sets the 802.1p bit to 110.
- For IPv4 and IPv6 packets, the software copies the IP type-of-service (ToS) value into the 802.1p field independently of which queue the packets are sent out.
- For MPLS packets, the software copies the EXP bits into
the 802.1p field.
Table 1: Routing Engine Protocol Queue Assignments
Routing Engine Protocol
Queue Assignment
Adaptive Services PIC
TCP tickle (keepalive packets for idle session generated with stateful firewall to probe idle TCP sessions) are sent from queue 0.
ATM Operation, Administration, and Maintenance (OAM)
Queue 3
Bidirectional Forwarding Detection (BFD) Protocol
Queue 3
Border Gateway Protocol (BGP)
Queue 0
BGP TCP Retransmission
Queue 3
Cisco High-Level Data Link Control (HDLC)
Queue 3
Distance Vector Multicast Routing Protocol (DVMRP)
Queue 3
Frame Relay Local Management Interface (LMI)
Queue 3
Frame Relay Asynchronization permanent virtual circuit (PVC)/data link connection identifier (DLCI) status messages
Queue 3
FTP
Queue 0
Intermediate System-to-Intermediate System (IS-IS) Open Systems Interconnection (OSI)
Queue 3
Internet Group Management Protocol (IGMP) query
Queue 3
IGMP Report
Queue 0
IP version 6 (IPv6) Neighbor Solicitation
Queue 3
IPv6 Neighbor Advertisement
Queue 3
IPv6 Router Advertisement
Queue 0
Label Distribution Protocol (LDP) User Datagram Protocol (UDP) hello
Queue 3
LDP keepalive and Session data
Queue 0
LDP TCP Retransmission
Queue 3
Link Aggregation Control Protocol (LACP)
Queue 3
Link Services (LS) PIC
If link fragmentation and interleaving (LFI) is enabled, all routing protocol packets larger then 128 bytes are transmitted from queue 0. This ensures that VoIP traffic is not affected. Fragmentation is supported on queue 0 only.
Multicast listener discovery (MLD)
Queue 0
Multicast Source Discovery Protocol (MSDP)
Queue 0
MSDP TCP Retransmission
Queue 3
Multilink Frame Relay Link Integrity Protocol (LIP)
Queue 3
Open Shortest Path First (OSPF) protocol data unit (PDU)
Queue 3
Point-to-Point Protocol (PPP)
Queue 3
Protocol Independent Multicast (PIM)
Queue 3
Real-time performance monitoring (RPM) probe packets
Queue 3
Resource Reservation Protocol (RSVP)
Queue 3
Routing Information Protocol (RIP)
Queue 3
Simple Network Management Protocol (SNMP)
Queue 0
SSH
Queue 0
Telnet
Queue 0
Virtual Router Redundancy Protocol (VRRP)
Queue 3
xnm-clear-text
Queue 0
xnm-ssl
Queue 0
