VDX port-channel and QoS

[kyungchan_tae]

Hello, 

I have configured the cir-rate to 4000000000 bps and added this to the port-channel. (outbound)

As I checked Interface stats, the port-channel TX Mbits/Sec is 8G, and the two physical interfaces are 4G each.

port-channel protocol is vLAG.
Is it correct to be assigned to each physical interface when constructing a cir-rate in vLag?

I listed my configuration below.

--------------------------------------------------------------------

1. Configuration

ip access-list extended DMI_QoS
 seq 10 permit ip any any
!
class-map DMI_QoS
 match access-group DMI_QoS
!
policy-map DMI_QoS
 class DMI_QoS
  police cir 4000000000
!
interface Port-channel 34
 vlag ignore-split
 speed 40000
 service-policy in DMI_QoS
 service-policy out DMI_QoS
 description To_A2-Private-BB
 switchport
 switchport mode trunk
 switchport trunk allowed vlan add 884
 switchport trunk tag native-vlan
 bpdu-drop enable all
 spanning-tree shutdown
 no shutdown
!
DMI-J04-Agg-1# show port-channel sum
Flags:  D - Down                P - Up in port-channel (members)
        U - Up (port-channel)   * - Primary link in port-channel
        S - Switched
        M - Not in use. Min-links not met
===== =============== ========== ===============
Group Port-channel    Protocol   Member ports   
===== =============== ========== ===============
34    Po 34   (SU)    vLAG       Fo 1/0/34* (P)
                                 Fo 2/0/34 (P)

---------------------------------------------------------------------------

2. Interface Stats

DMI-J04-Agg-1# show int stats detail int for 1/0/34
 Interface FortyGigabitEthernet 1/0/34 statistics (ifindex 4496572608)
                                   RX                              TX
             Packets   1370691649661                    981336658925
               Bytes1524991468632748                1059188641765505
            Unicasts   1370679886980                    981330835439
          Multicasts         8453727                         3866220
          Broadcasts         3308959                         1957266
              Errors               0                               0
            Discards          257494                               0
            Overruns               0       Underruns               0
               Runts               0
             Jabbers               0
                 CRC               0
        64-byte pkts     35217295304
   Over 64-byte pkts    315759386904
  Over 127-byte pkts     16635043142
  Over 255-byte pkts     16543705056
  Over 511-byte pkts      6712835637
 Over 1023-byte pkts    134655136037
 Over 1518-byte pkts    845168247582
           Mbits/Sec     3409.026464                     3998.462396
          Packet/Sec          470671                          436433
           Line-rate           8.71%                          10.17%

DMI-J04-Agg-1# show int stats detail int for 2/0/34
 Interface FortyGigabitEthernet 2/0/34 statistics (ifindex 8791539904)
                                   RX                              TX
             Packets          291782                    136788046082
               Bytes        33753254                 164605538829245
            Unicasts          118363                    136787873661
          Multicasts          173419                          172421
          Broadcasts               0                               0
              Errors               0                               0
            Discards               0                               0
            Overruns               0       Underruns               0
               Runts               0
             Jabbers               0
                 CRC               0
        64-byte pkts           67794
   Over 64-byte pkts           50569
  Over 127-byte pkts          173419
  Over 255-byte pkts               0
  Over 511-byte pkts               0
 Over 1023-byte pkts               0
 Over 1518-byte pkts               0
           Mbits/Sec        0.000000                     4014.862272
          Packet/Sec               0                          330840
           Line-rate           0.00%                          10.17%

DMI-J04-Agg-1# show int stats detail int port 34   
 Interface Port-channel 34 statistics (ifindex 671088674)
                                   RX                              TX
             Packets   1370704340265                   1118150299673
               Bytes1524995191395681                1223832186925037
            Unicasts   1370692404236                   1118144303799
          Multicasts         8627047                         4038586
          Broadcasts         3308985                         1957288
              Errors               0                               0
            Discards          257494                               0
            Overruns               0       Underruns               0
               Runts               0
             Jabbers               0
                 CRC               0
        64-byte pkts     35217363116
   Over 64-byte pkts    315769953516
  Over 127-byte pkts     16635231057
  Over 255-byte pkts     16543730353
  Over 511-byte pkts      6712847918
 Over 1023-byte pkts    134655150594
 Over 1518-byte pkts    845170063712
           Mbits/Sec      140.565704                     8011.224900
          Packet/Sec          177950                          660577
           Line-rate           0.18%                          10.01%

many thanks.

[kyungchan_tae]

Hi Truyen,

Your answer was very helpful.

Thanks.

[Truyen_Phan]

Yes, I believe there will be a difference in results:

1. Two port-channel members are configured in two R-brides. (Ex : Te 1/0/1, Te 2/0/1)

This is the result you were seeing:

• Port-channel 1 stats : TX,RX limit of 8000 Mbits/Sec

• Two physical interfaces stats : TX,RX limit of 4000 Mbits/Sec

2. Two port-channel members are configured in one R-bridge. (Ex : Te 1/0/1, 1/0/2)

For this one, I would expect this result:

• Port-channel 1 stats : TX,RX limit of 4000 Mbits/Sec

• Two physical interfaces stats : TX,RX limit of 2000 Mbits/Sec on each interface

[kyungchan_tae]

I'm sorry to confuse you.

I think my LACP explanation was insufficient.

I wanted to know if there was a difference in the interface to which Cir-rate is assigned under the two conditions below.

1. Two port-channel members are configured in two R-brides. (Ex : Te 1/0/1, Te 2/0/1)
2. Two port-channel members are configured in one R-bridge. (Ex : Te 1/0/1, 1/0/2)

Will both of these conditions result in the following results?

• Port-channel 1 stats : TX,RX limit of 8000 Mbits/Sec

• Two physical interfaces stats : TX,RX limit of 4000 Mbits/Sec

Thank you for your kind reply.

[Truyen_Phan]

• I expected that if we apply cir-rate of 4000000000 bps (Up to 4000 Mbits/Sec) to port-channel, the TX,RX limit of port-channel is 4000 Mbits/Sec.

• However, the TX,RX limit for this port-channel is 8000 Mbits/Sec.

Not sure if my previous response was clear. As mentioned, the port-channel configuration is a global configuration that both RB 1 and RB 2 are part of. However, each RB handles it’s traffic locally when it’s received. 

For example, both RBs receives traffic, since each RB has a port which are part of PO 34, each will RX,TX max of 4000 Mbit/sec according to the cir-rate. If you have another port added which connect to RB1 or RB2, then it will be split among those ports which are locally on the same RB. 

• If this is normal, we will apply a cir-rate of 2000000000 bps (Up to 2000 Mbits/Sec) to port-channel and expect a TX,RX limit of 4000 Mbits/Sec

If you are looking to limit only 2000 Mbits/Sec to each interface on PO 34 which only has 2 interfaces that are part of RB1 and RB2, then setting the cir-rate to 2000000000 bps is correct. 

According to what you mentioned, there is no difference in the cir-rate limit depending on the protocol type of the port channel. (vLag, LACP)

For example, even if only port-channel protocol was changed to LACP in the configuration that I initially shared, the port-channel TX,RX limit would be 8000 Mbits/Sec just like vLag. (The TX,RX limit of the two physical interfaces is 4000 Mbits/Sec)

Is this understanding correct?

vLAG just means that the port-channel is connected/configured to multiple (different) R-Bridges. In this case, RB 1 and RB 2. Logically, RB 1 and RB 2 form the vLAG which talks LACP protocol for the port-channel. So, technically, you are already configured for both as a vLAG to use LACP protocol. 

Hope that clears it up a bit.