KVM consuming all the bandwith on LACP connection

[robertkwild]

hi all,

i have two cisco switches (4510 and a SG350X) connected together via LACP 2x1g either side so 4x1g one side is an "active" (4510) connection and the other side is set to "auto" (SG350X) and both port channels either end say "connected"

i set both sides to "auto" but both sides said "not connected" so i changed one to "active" and happy days

my problem is i have a KVM device connected to my SG350X and that is consuming alot of bandwith so i would just like to know the best LACP configuration ie load balancing etc?

cheers,

rob

[Seb Rupik]

Hi there,

Are the devices connecting to the KVM situated on different subnets? If so, then choose a hashing algorithm which uses both src-dst-ip. If connecting devices are on the same subnet then go for src-dst-mac .

Not sure what options you have available on the SG350.

cheers,

Seb.

[robertkwild]

the KVM vlan is 240 so i have created vlan 240 etiher side and trunked it down the port-channel

4510 has these options

4510MCR01(config)#port-channel load-balance ?
dst-ip Dst IP Addr
dst-mac Dst Mac Addr
dst-port Dst TCP/UDP Port
src-dst-ip Src XOR Dst IP Addr
src-dst-mac Src XOR Dst Mac Addr
src-dst-port Src XOR Dst TCP/UDP Port
src-ip Src IP Addr
src-mac Src Mac Addr
src-port Src TCP/UDP Port

and the SG350X has these options

studio1(config)#port-channel load-balance
src-dst-mac-ip Port channel load balancing is based on source and
destination of MAC and IP addresses.
src-dst-mac Port channel load balancing is based on source and
destination MAC address.

how can i see what load-balancing it is using?

[Seb Rupik · Accepted solution]

show port-channel load-balance

...it is global setting for the entire switch.

Based on your options, go for:

4500 : src-dst-ip

SG350: src-dst-mac-ip

cheers,

Seb.

[robertkwild]

but dont both sides need to match ie if i set one to "src-dest-mac" doesnt the other side need to be the same?

but with the port channel mode as the SG350X doesnt do active i can only set it to auto

[Seb Rupik]

The hashing algorithm is locally significant and does not need to match on either end of the port-channel.

Ideally they should be the same both ends, but given your hashing options on the different platforms, they are close enough.

[robertkwild]

another quick question, as both devices are cisco shall i use pagp or lacp?

[Seb Rupik]

LACP without a second thought. Even Cisco is supporting pagp on less hardware.

[Joseph W. Doherty]

"Ideally they should be the same both ends, but given your hashing options on the different platforms, they are close enough."

BTW, depending on what your device hashing options are, and the nature of the traffic, sometimes both ends should NOT be the same choice.

For example, given only src or dest MAC or IP hashing, and give a server to multiple hosts, server to hosts should use dest hashing and hosts to server should use src hashing.

Today, most devices offer combined src/dest hashing, and that will work for the prior in either direction.

Also today, most device offer combined src/dest IP hashing, which if often a better choice than MAC hashing as IP hashing deals with IP gateways along with same LAN hosts.

[rasmus.elmholt]

As a general recommendation you should go as far up the OSI stack as possible.
If the devices support L4 then you should use that for loadbalancing.

[robertkwild]

also i have done all my configuration under #int port-channel 2 and not #int range g2/1-2 ie

#int range g2/1-2

#channel-group 2 mode active

#int port-channel 2

#switchport mode trunk

#switchport trunk allowed vlan (1,2,3 etc...)

#no shut

#end

is it best to do the same for the individual gig ports aswell as the port channel group?