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JVV_137012's avatar
JVV_137012
Icon for Nimbostratus rankNimbostratus
Nov 06, 2013
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Can one host/node be part of multiple VLANs?

This is not really an F5-specific question, but will help me clarify few VLAN/trunking concepts.

 

Q: Can one host/node be part of multiple VLANs? For example, on my Linux host if I exec the following commands, will it receive packets for VLAN 1234 and VLAN 4567 both? (provided all other network configurations have been done and are working).

 

vconfig add eth0 1234 vconfig add eth0 4567

 

Thanks, JVV

 

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vlan
  • dathomas111_201's avatar
    dathomas111_201
    Nov 06, 2013

    Mulitple nics will put the host on multiple network segments which would each carry their respective vlan traffic. If the node is a VM host then a 802.1q trunk can carry multiple vlans to that host to be configured for different VM guest machines that require separate connectivity. The vlan tag you see at the interface level would be dependent on how the local switch (virtual or network) is delivering that connectivity to the host.

     

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  • dathomas111_201's avatar
    dathomas111_201
    Icon for Altocumulus rankAltocumulus
    Nov 06, 2013

    Mulitple nics will put the host on multiple network segments which would each carry their respective vlan traffic. If the node is a VM host then a 802.1q trunk can carry multiple vlans to that host to be configured for different VM guest machines that require separate connectivity. The vlan tag you see at the interface level would be dependent on how the local switch (virtual or network) is delivering that connectivity to the host.

     

    • JVV_137012's avatar
      JVV_137012
      Icon for Nimbostratus rankNimbostratus
      Nov 06, 2013
      Thanks! Just out of curiosity, can it be possible with only one interface? Please see below for ifconfig on my Linux VM ~~~ [root@jv-centos64-clean ~] ifconfig -a eth0 Link encap:Ethernet HWaddr 00:0C:29:ED:29:19 inet addr:192.168.142.143 Bcast:192.168.142.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:feed:2919/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:1065 errors:0 dropped:0 overruns:0 frame:0 TX packets:433 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:101708 (99.3 KiB) TX bytes:72006 (70.3 KiB) eth0.1234 Link encap:Ethernet HWaddr 00:0C:29:ED:29:19 BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) eth0.2345 Link encap:Ethernet HWaddr 00:0C:29:ED:29:19 BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) ~~~
    • IheartF5_45022's avatar
      IheartF5_45022
      Icon for Nacreous rankNacreous
      Nov 07, 2013
      I'm not a Linux person but that looks as I would expect, however you would have to check with your VCentre (or equivalent) adminstartor to see how the port-profiles have been configured - to present 802.1q tags on a single interface as you seem to be expecting, or whether they present each VLAN as a separate interface? Also BTW 802.1q trunks are by no means the province of virtualised environments - they have been round for ever......