I have a question about the network configuration when connecting 2 switches in a colocation rack via 2 uplinks (1 uplink to each switch) to 2 other switches of the datacenter itself.

My topology looks at the moment like this:

I have a colocation rack with 2 switches (2x DELL S6000-ON). Between both switches an ISL is set up. Every host has 2 NICs, each connected to one switch. The connection between the hosts and the switches is working via MLAG/LACP.

Now I have 2 uplinks going into my rack. Each uplink is connected to a different switch within the datacenter, also for redundancy. Their gateway is also redundant via VRRP.

Now my question: How to properly interconnect my 2 switches with their 2 switches, when having only 2 uplinks? MLAG would not work, correct? For MLAG I would need at least 4 uplinks, right? What other "technology" can I use to interconnect my 2 switches with the 2 switches of the DC for redundancy/fail-over? ECMP maybe? Some kind of L3 routing? BGP/OSPF? Or better just rent additional 2 more uplinks to do MLAG?

I'm sorry for this probably "noob-question". I'm not really the networking guy. It's enough for me if you just give me a hint like "ECMP" and then I will look up everything about it... :)

Thank you very much in advance! Greetings from Germany, Andreas

  • It's not clear that MLAG would not work. Have you talked to the datacenter people?
    – Ron Trunk
    Mar 22, 2019 at 12:09
  • @RonTrunk Not directly, because I thought I need at least 4 uplinks to do MLAG between my 2 switches and the 2 switches of the datacenter. Or am I wrong here? Can I do a MLAG when I have only a connection between DCswitch1 <-> MySwitch1 and DCswitch2 <-> MySwitch2? In many network topology pictures they had additionally a connection between DCswitch1 <-> MySwitch2 and DCswitch2 <-> MySwitch1. So in total 4 links between the 2:2 switches.
    – Andreas B.
    Mar 22, 2019 at 20:18


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