Default Routing Engine Protocol Queue Assignments
Table 1 lists the default output queues to which Routing Engine sourced traffic is mapped by protocol type. In general, control protocol packets are sent over queue 3 and management traffic is sent over queue 0. The following caveats apply to these default queue assignments:
-
For all packets sent to queue 3 over a VLAN-tagged interface, the software sets the 802.1p bit to 110, except for VRRP packets, in which case the software sets the 802.1p bit to 111.
-
Outgoing BFD packets should be marked with VLAN-tagged 802.1p bit to 110; however, this is true only for RE based BFD. For inline BFD, it does not modify by default.
- Although BGP and LDP TCP traffic is sent to queue 0, it is marked with 802.1p bits 110 normally used for network control.
-
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.
Routing Engine Protocol |
Default Queue Assignment |
|---|---|
|
Adaptive Services PIC TCP tickle (keepalive packets for idle session generated with stateful firewall to probe idle TCP sessions) |
Queue 0 |
|
Address Resolution Protocol (ARP) |
Queue 0 |
|
ATM Operation, Administration, and Maintenance (OAM) |
Queue 3 |
|
Bidirectional Forwarding Detection (BFD) Protocol |
Queue 3 |
|
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 |
|
Ethernet Operation, Administration, and Maintenance (OAM) |
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 |
|
IS-IS Open Systems Interconnection (OSI) |
Queue 3 |
|
Internet Control Message Protocol (ICMP) |
Queue 0 |
|
Internet Group Management Protocol (IGMP) query |
Queue 3 |
|
IGMP Report |
Queue 0 |
|
Internet Key Exchange (IKE) |
Queue 3 |
|
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 |
|
NETCONF |
Queue 0 |
|
NetFlow |
Queue 0 |
|
OSPF protocol data unit (PDU) |
Queue 3 |
|
Point-to-Point Protocol (PPP) |
Queue 3 |
|
Protocol Independent Multicast (PIM) |
Queue 3 |
|
Precision Time Protocol (PTP) |
Queue 3 |
|
Real-time performance monitoring (RPM) probe packets |
Queue 3 |
|
RSVP |
Queue 3 |
|
Routing Information Protocol (RIP) |
Queue 3 |
|
SNMP |
Queue 0 |
|
SSH |
Queue 0 |
|
sFlow monitoring technology |
Queue 0 |
|
Telnet |
Queue 0 |
|
Two-Way Active Monitoring Protocol (TWAMP) |
Queue 0 |
|
Virtual Router Redundancy Protocol (VRRP) |
Queue 3 |
|
|
Queue 0 |
|
|
Queue 0 |