Description

This article explains why IPv4 Multicast packets do not hit the Policer when they are applied in the egress direction on Ichip-based platforms.

Symptoms

M320 E3-FPC Type 2 (Ichip)

Topology/Configuration

+-----+                                                         +-------+
|ixia1|------>(xe-1/1/0)M320(ge-7/0/4)----------------MX-480----|IXIA 2 |
+-----+                 M320 E3-FPC Type2 (Ichip)               +-------+


The ge-7/0/4 interface is on the FPC7 (the Ichip):

lab@m320> show chassis hardware | match "fpc 7"
FPC 7            REV 07   710-016170   WL2586            M320 E3-FPC Type 2

Policer Configuration

set firewall policer 512k if-exceeding bandwidth-limit 512k
set firewall policer 512k if-exceeding burst-size-limit 10k
set firewall policer 512k then discard


Applying Policer on Outbound Interface

set interfaces ge-7/0/4 unit 0 family inet policer output 512k
set interfaces ge-7/0/4 unit 0 family inet address 10.254.1.214/30


Unicast: Sending Unicast Packet with 3000000 bps

The input interface (xe-1/1/0) is receiving 3004800 bps unicast packets:

lab@m320# run show interfaces xe-1/1/0 | match "Input rate"
Input rate     : 3004800 bps (313 pps)

The output interface (ge-7/0/4 ) is sending 512 Kbps of unicast traffic.

For unicast traffic, the Policer is being hit and policing at the rate of 512K :

lab@m320# run show interfaces ge-7/0/4 | match Output
Output rate : 518400 bps (54 pps)
Output packets: 34429
lab@m320# run show interfaces ge-7/0/4 | match Output
Output rate : 528000 bps (55 pps)
Output packets: 34538

The command output below shows that 512000 bps are able to be sent:

lab@m320# run show interfaces queue ge-7/0/4 egress | match "Trans|Byte"
Bytes                :           22861195143                520672 bps
Transmitted:
Packets              :              45002579                     54 pps
Bytes                :           22861195143                520672 bps
RED-dropped bytes    :                     0                     0 bps
Bytes                :                     0                     0 bps
Transmitted:0                     0 bps


Multicast: Sending Multicast Packet at 3000000 bps

The traffic is now changed to multicast:

lab@m320# run show interfaces xe-1/1/0 | match "Input rate"
Input rate     : 3004800 bps (313 pps)

{MASTER}[edit]
lab@m320# run show interfaces xe-1/1/0 | match "Input rate"
Input rate     : 2995200 bps (312 pps)
Input rate is 3 Mbps on xe-1/1/0 ( Incoming interface ).
lab@m320# run show interfaces ge-7/0/4 | match Output
Output rate : 2995200 bps (312 pps)
Output packets: 112213

lab@m320# run show interfaces ge-7/0/4 | match Output
Output rate : 2995200 bps (312 pps)
Output packets: 113463
lab@m320# run show interfaces queue ge-7/0/4 egress | match "Trans|Byte"
Bytes                :           22946720839               3000000 bps
Transmitted:
Packets              :              45073860                    312 pps
Bytes                :           22946720839               3000000 bps
RED-dropped bytes    :                     0                     0 bps
Bytes                :                     0                     0 bps

The packet count in the policer output is zero:

lab@m320# run show policer 512k-ge-7/0/4.0-inet-o

Policers:
Name                                                Bytes              Packets
512k-ge-7/0/4.0-inet-o                                                     0

{MASTER}[edit]
lab@m320# run show policer 512k-ge-7/0/4.0-inet-o
Policers:
Name                                                Bytes              Packets
512k-ge-7/0/4.0-inet-o                                                     0

For Multicast traffic, the policer is not being hit. The input rate is 3 Mbps, and the output interface is passing with the same rate without filtering.

The PFE output shows that the policer is programmed correctly:

% cprod -A fpc7 -c "show filter index 17009 program"

Program Filters:
---------------
Index     Dir     Cnt    Text     Bss  Name
--------  ------  ------  ------  ------  --------
17009      52       0       4       4  512k-ge-7/0/4.0-inet-o

Firewall program version 18 magic fed2beef
Name: "512k-ge-7/0/4.0-inet-o"  Protocol: ip  Flags: 0x01
Implicit Filter: No
Hash: 5ed725379bed25bf7b20ef4e04ab78dd
Action directory: 1 entry (52 bytes)
Policer directory: 1 entry (176 bytes)
Text: 1 instruction word (4 bytes)
BSS: 10 next hop words (40 bytes)
Action directory: 1 entry (52 bytes)
0: accept policer 0
-> 0:
Policer directory: 1 entry (176 bytes)
0: Policer name "512k-ge-7/0/4.0-inet-o": 1 reference
Bandwidth Limit: 64000 bytes/sec.
Burst Size: 10000 bytes.
discard
Program instructions: 1 word 0: terminate -> action index 0 % For Ichip Policer is not getting hit for multicast traffic in outbound direction.


Modular Port Concentrator (MPC)

Topology

+-----+                                                          +-------+
|ixia2|------>( xe-2/1/0)MX480(ge-2/3/8)-------------M-320--- --|IXIA 1 |
+-----+ MPCE Type 2 3D Q (Trio)                                  +-------+


The Policer configuration here is the same as the Policer configuration for the M320 E3-FPC Type 2 (Ichip), above.

The ge-2/3/8 interface is on the FPC2 (the MPC):

lab@MX-480-1-RE1# run show chassis hardware | match "FPC 2"
FPC 2            REV 09   750-038493   CAAF7653          MPCE Type 2 3D Q


Multicast: Sending Multicast Packet with 3000000 bps

The input rate on the Input interface (xe-2/1/0) is 2156200 bps:

[edit]
lab@MX-480# run show interfaces xe-2/1/0 | match "Input rate"
Input rate     : 2156056 bps (5858 pps)

The outbound interface (ge-3/1/0) is sending 1022728 bps:

ab@MX-480# run show interfaces ge-2/3/8 | match Output
Output rate : 511344 bps (1389 pps)
Output packets: 7382158
[edit]
lab@MX-480# run show interfaces ge-2/3/8 | match Output
Output rate : 511536 bps (1389 pps)
Output packets: 7384921
[edit]
lab@MX-480# run show interfaces ge-2/3/8 | match Output
Output rate : 513016 bps (1394 pps)
Output packets: 7387693
Interface: ge-2/3/8, Enabled, Link is Up
Encapsulation: Ethernet, Speed: 1000mbps
Traffic statistics: Current delta
Input bytes: 542837602 (0 bps) [0]
Output bytes: 342039430 (513760 bps) [636092]
Input packets: 459714 (0 pps) [0]
Output packets: 7434806 (1395 pps) [13827]

The Drop count in the Policer is incrementing:

[edit]
lab@MX-480# run show policer 512k-ge-2/3/8.0-inet-o
Policers:
Name Bytes Packets
512k-ge-2/3/8.0-inet-o 37618570 817795
[edit]
lab@MX-480# run show policer 512k-ge-2/3/8.0-inet-o
Policers:
Name Bytes Packets
512k-ge-2/3/8.0-inet-o 37618570 817795

[edit]
lab@MX-480# run show policer 512k-ge-2/3/8.0-inet-o
Policers:
Name Bytes Packets
512k-ge-2/3/8.0-inet-o 38027464 826684
% cprod -A fpc2 -c "show filter index  17001 program"

Filter index = 17001
Optimization flag: 0x0
Filter notify host id = 0
Filter properties: None
Filter state = CONSISTENT
term default
term priority 0

then
accept
policer template 512k
policer 512k-ge-2/3/8.0-inet-o
app_type 0
bandwidth-limit 512000 bits/sec
burst-size-limit 10000 bytes
discard
%

Conclusion

As shown above, the MPC (Trio) is hitting the Policer and policing the multicast traffic.

Solution


The Policer works for Multicast traffic on the Modular Port Concentrator (MPC) in the output direction.

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