Introduction
When troubleshooting CoS related problems or testing CoS features it is often useful to be able to view the class of service of packets as they enter your router. If packets are not entering your router with the correct markings they will not be assigned to the correct forwarding class and will not receive the desired CoS treatment. Oddly, there does not seem to be a JUNOS command that displays counters of ingress markings. One way around this is to use an inbound firewall filter that matches and counts ingress packets based on their markings.
Junos Configuration
To configure this feature you have to configure the right type of firewall filter for the packest you want to count and for the encapsulation of the ingress interface you want to count them on.
Following are two examples, the first for PCP bits (802.1p bits in a VLAN header) and second EXP bits (CoS bits in an MPLS header). Both examples assume you have already configured the appropriate schedulers, and scheduler-map for the interface. The first example matches on forwarding class and therefore assumes you have non-default forwarding classes configured:
forwarding-classes {
queue 0 Network priority high;
queue 1 Gold priority high;
queue 2 Silver priority low;
queue 3 Bronze priority low;
queue 4 BestEffort priority low;
The second example matches on bit pattern alias and therefore assumes you have configured a code point alias map for the EXP bits:
code-point-aliases {
exp {
exp0 000;
exp1 001;
exp2 010;
exp3 011;
exp4 100;
exp5 101;
exp6 110;
exp7 111;
Viewing PCP on an interface using “vlan-bridge” encapsulation.
Configure the filter
set firewall family any filter incoming_class term Network from forwarding-class Network set firewall family any filter incoming_class term Network then count Network set firewall family any filter incoming_class term Gold from forwarding-class Gold set firewall family any filter incoming_class term Gold then count Gold set firewall family any filter incoming_class term Silver from forwarding-class Silver set firewall family any filter incoming_class term Silver then count Silver set firewall family any filter incoming_class term Bronze from forwarding-class Bronze set firewall family any filter incoming_class term Bronze then count Bronze set firewall family any filter incoming_class term BestEffort from forwarding-class BestEffort set firewall family any filter incoming_class term BestEffort then count BestEffort set firewall family any filter incoming_class term accept then accept
Apply to the appropriate interface
set interfaces xx-x/x/x unit xxx filter input incoming_class
Clear counters
clear firewall filter incoming_class
Viewing Counters
user@router_name> show firewall filter incoming_class Filter: incoming_class Counters: Name Bytes Packets BestEffort 0 0 Silver 0 0 Network 46436 684 Gold 1771637284 9133411 Bronze 0 0
Viewing EXP on an interface using “Ethernet” encapsulation
Configure the filter
set firewall family mpls filter incoming_exp term 7 from exp 7 set firewall family mpls filter incoming_exp term 7 then count exp7 set firewall family mpls filter incoming_exp term 6 from exp 6 set firewall family mpls filter incoming_exp term 6 then count exp6 set firewall family mpls filter incoming_exp term 5 from exp 5 set firewall family mpls filter incoming_exp term 5 then count exp5 set firewall family mpls filter incoming_exp term 4 from exp 4 set firewall family mpls filter incoming_exp term 4 then count exp4 set firewall family mpls filter incoming_exp term 3 from exp 3 set firewall family mpls filter incoming_exp term 3 then count exp3 set firewall family mpls filter incoming_exp term 2 from exp 2 set firewall family mpls filter incoming_exp term 2 then count exp2 set firewall family mpls filter incoming_exp term 1 from exp 1 set firewall family mpls filter incoming_exp term 1 then count exp1 set firewall family mpls filter incoming_exp term 0 from exp 0 set firewall family mpls filter incoming_exp term 0 then count exp0 set firewall family mpls filter incoming_exp term accept then accept
Apply to the appropriate interface
set interfaces xx-x/x/x unit 0 family mpls filter input incoming_exp
Clear counters
clear firewall filter incoming_exp
View counters
user@router_name> show firewall filter incoming_exp Filter: incoming_exp Counters: Name Bytes Packets exp0 6292252 6192 exp1 8591442 13403 exp2 0 0 exp3 19965 175 exp4 0 0 exp5 2596646 11741 exp6 0 0 exp7 3132 22