Question on Uplinks and Network Maximum Ports

ande0255

I believe I have this right, but wanted to clarify a couple of things from the networking chapter of Mastering vSphere 5.

When it comes to uplinks, when NIC Teaming is in use, are there certain conditions under which multiple NIC's are considered one uplink? Like if NIC's are performing load-balancing via link status / source MAC / IP Hash, are those considered one uplink, as if I understand correctly they must all be connected to the same physical switch in the same broadcast domain?

Also, in regards to the maximum question, kind of a weird # thrown at the bottom of the ESXi host maximum configurations - Maximum active ports per host: 1016. This strikes me as odd, as it shows the maximum number of ports per vSwitch above that as 4,088, so does this mean that although there are 4,088 ports available for use that only 1/4 of them can be active at any given time?

I could probably google it, but I figure posting on here maybe can help someone down the road with a similar question. I plan to break out a switch to hook up to my laptop, and see if I can configure some network configuration to the vSwitch in my nested lab, will probably be a thread on that too once I get my arse in gear

Thanks!

Essendon

Good questions mate.

- NIC teaming: originating port ID and source MAC hash do no load balancing at all, just redundancy. Traffic will continue to use the same uplink for the entirety of the session. If the uplink goes down for whatever reason, the other one in the team is used. A VM is limited to the bandwidth provided by one uplink. IP hash, something I am not a fan of, will only help if your VM needs to communicate with multiple destinations. If there's a single destination, no load balancing is done. It just uses the same uplink throughout the session.

- Yes, your right the uplinks need to be on the same switch (or stacked switches)

- maximum number of ports/host = 4088 (actually 4096, but 8 are reserved by ESXi). So you could have 4088 dished out by one vSS or multiple vSS's. Keep in mind that these vCenter imposed limits are soft limits but the ones enforced by ESXi are hard limits. Maximum number of ports in use by the host at any one time = 1016.

scott28tt

One slight point of clarity - assuming you have multiple VMs connected to a port group with multiple active NICs in a NIC team, you will get traffic "balanced" across the NICs when using the originating port ID or source MAC hash configurations.

Traffic to/from some of the VMs will pass through one NIC, and to/from other VMs through other NICs in the team. What won't happen is the traffic from a single VM being "balanced".

jibbajabba

Essendon wrote: »

<snip>
IP hash
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- Yes, your right the uplinks need to be on the same switch (or stacked switches)
<snip>

Not to forget, when using IP Hash your uplinks need to be configured in a channel group / port channel on the physical stack.

Personally I would go with load based teaming any day