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.
  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 than 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
  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