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Bundle-Ether Load Balancing

mirkolobina
Level 1
Level 1

hi all, i have anissue due to a possibile misconfig with load-balan in an lacp. my platform is asr9001 with ios-xr 5.3.3. this device is connected to a switch with two bundled lacp ports. the be interface + phy are configured this way:

 

interface Bundle-Ether102.2110
 vrf lte-gtp-bearer
 ipv4 address 10.247.112.1/24
 ipv4 unreachables disable
 encapsulation dot1q 2110

 

interface GigabitEthernet0/0/0/10 - 11
 bundle id 102 mode active
 lacp period 100
 load-interval 30

 

basically what i have here is the default gw for a lan connected to a switch reachable via be. the problem is in the download part (output of be102 to the switch).

 

the tipology of traffic present is many sources in the lan to only one destination reachable via default gw. so the return traffic should be hashed from one src ip to many dst ip, and , afaik, being a l2 should be a l2 hashing.

 

so:

1) i have found the possibility of a l2 balancing only under a l2vpn. which is not my case

2) wrong thing if i try to balance per dst-ip

3) any help very very welcome

 

below some pasted output:

 

RP/0/RSP0/CPU0:a9001.rmc-core-lte-01#sh bundle bundle-ether 102
Wed Sep 27 08:15:33.452 CET

Bundle-Ether102
  Status:                                    Up
  Local links <active/standby/configured>:   2 / 0 / 2
  Local bandwidth <effective/available>:     2000000 (2000000) kbps
  MAC address (source):                      78ba.f90d.5443 (Chassis pool)
  Inter-chassis link:                        No
  Minimum active links / bandwidth:          1 / 1 kbps
  Maximum active links:                      64
  Wait while timer:                          2000 ms
  Load balancing:                            Default
  LACP:                                      Operational
    Flap suppression timer:                  Off
    Cisco extensions:                        Disabled
    Non-revertive:                           Disabled
  mLACP:                                     Not configured
  IPv4 BFD:                                  Not configured

  Port                  Device           State        Port ID         B/W, kbps
  --------------------  ---------------  -----------  --------------  ----------
  Gi0/0/0/10            Local            Active       0x8000, 0x0003     1000000
      Link is Active
  Gi0/0/0/11            Local            Active       0x8000, 0x0002     1000000
      Link is Active

 

RP/0/RSP0/CPU0:a9001.rmc-core-lte-01#sh bundle-hash adv-lb bundle-ether 102.2110
Wed Sep 27 08:16:02.318 CET
Interface     Type     Load Balance      Selected Member

 

 

1 Reply 1

Rich Uline
Level 1
Level 1

Mirkolobina,

 

The default hashing for IPv4 traffic uses the router ID, source and destination IP, and source and destination port. This should provide enough variance to load balance properly.

You could try altering the hashing method for that interface only using something like this:

interface Bundle-Ether102
  bundle load-balancing hash src-ip

Or, you could try globally changing the way the hash is calculated.
Something like this will shift the hash bit:

cef load-balancing algorithm adjust 3

Something like this will force the router to exclude the source and destination port in the hash calculation:

cef load-balancing fields L3 global
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