Server cannot use 1000-Base and 100-Base NIC at same time

[leowchongwei]

Had a server with built-in NIC for 1000Base and 100Base. However, when plug both into the switch. Only 1 can work. And the 100Base is preferred over the 1000Base. My friend told me could be due to spanning tree at blocking state. How true is this? Is it more appropriate to plug the 2 NIC into different switches?

[psijnja]

It can only be a spanningtree problem if the NICs use the same MAC address.

Spanningtree is a Layer2 loop prevention protocol, it would only find a layer 2 loop if the MAC addresses were the same.

[scottmac]

A server using multiple NICs would usually plug into different switches.

If the two switches are in the same broadcast domain (same vlan/subnet), then one would normally be up/active and the other would be in a standby mode (for failover redundancy).

If the NICs support "Teaming" (parallel paths to multiply bandwidth) they must be connected to a switch that also supports teaming (I believe it requires Etherchannel / FastEtherchannel support).

How would you like to use the two ports? For additional bandwidth, for fail-over / redundancy, or as a "public" connection with a "private" management interface?

Scott

[leowchongwei]

hi Scott,

We are thinking of additional bandwidth as priority. Can EtherChannel be used NIC with different bandwidth? Any configuration need to be done on the server side? Thanks

Steven

[psijnja]

As far as I can tell it is not posible to have a channel of links with different bandwidth. Everything I've read suggest link of the same BW.

there is configuration needed on the server side of the channel. I'm not a server guy so I don't know what, but the NICs need to support it, and it needs to be enabled.

Pim

[scottmac]

I'm pretty certain that teaming / channel aggregation must use comparable NICs or ports (all 10,100, or Gig).

I haven't seen any specific documentation, but I also believe that all NICs must be (should be) from the same vendor - interoperability of one vendor's NIC drivers with a second vendor's NIC drivers is not likely, even though they are performing the same basic function.

Good Luck

Scott