Specific DSCP, forwarding class, and Dot1P parameters can be specified to be used by every protocol packet generated by the VPRN. This enables prioritization or de-prioritization of every protocol (as required). The markings effect a change in behavior on ingress when queuing. For example, if OSPF is not enabled, then traffic can be de-prioritized to best effort (be) DSCP. This change de-prioritizes OSPF traffic to the CPU complex.
DSCP marking for internally generated control and management traffic by marking the DSCP value should be used for the specific application. This can be configured per routing instance. For example, OSPF packets can carry a different DSCP marking for the base instance and then for a VPRN service. ISIS and ARP traffic is not an IP-generated traffic type and is not configurable. See Table: DSCP/FC marking .
When an application is configured to use a specified DSCP value then the MPLS EXP, Dot1P bits are marked in accordance with the network or access egress policy as it applies to the logical interface the packet is egressing.
The DSCP value can be set per application. This setting is forwarded to the egress line card. The egress line card does not alter the coded DSCP value and marks the LSP-EXP and IEEE 802.1p (Dot1P) bits according to the appropriate network or access QoS policy.
| Protocol | IPv4 | IPv6 | DSCP marking | Dot1P marking | Default FC |
|---|---|---|---|---|---|
ARP |
— |
— |
— |
Yes |
NC |
BGP |
Yes |
Yes |
Yes |
Yes |
NC |
BFD |
Yes |
— |
Yes |
Yes |
NC |
RIP |
Yes |
Yes |
Yes |
Yes |
NC |
PIM (SSM) |
Yes |
Yes |
Yes |
Yes |
NC |
OSPF |
Yes |
Yes |
Yes |
Yes |
NC |
SMTP |
Yes |
— |
— |
— |
AF |
IGMP/MLD |
Yes |
Yes |
Yes |
Yes |
AF |
Telnet |
Yes |
Yes |
Yes |
Yes |
AF |
TFTP |
Yes |
— |
Yes |
Yes |
AF |
FTP |
Yes |
— |
— |
— |
AF |
SSH (SCP) |
Yes |
Yes |
Yes |
Yes |
AF |
SNMP (get, set, and so on) |
Yes |
Yes |
Yes |
Yes |
AF |
SNMP trap/log |
Yes |
Yes |
Yes |
Yes |
AF |
syslog |
Yes |
Yes |
Yes |
Yes |
AF |
OAM ping |
Yes |
Yes |
Yes |
Yes |
AF |
ICMP ping |
Yes |
Yes |
Yes |
Yes |
AF |
Traceroute |
Yes |
Yes |
Yes |
Yes |
AF |
TACPLUS |
Yes |
Yes |
Yes |
Yes |
AF |
DNS |
Yes |
Yes |
Yes |
Yes |
AF |
SNTP/NTP |
Yes |
— |
— |
— |
AF |
RADIUS |
Yes |
— |
— |
— |
AF |
Cflowd |
Yes |
— |
— |
— |
AF |
DHCP 7450 ESS and 7750 SR only |
Yes |
Yes |
Yes |
Yes |
AF |
Bootp |
Yes |
— |
— |
— |
AF |
IPv6 Neighbor Discovery |
Yes |
— |
— |
— |
NC |