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SulemanTajik's avatar
SulemanTajik
Icon for Nimbostratus rankNimbostratus
Oct 26, 2017

How can we create P2P route b/w L3 upstream device and F5 for routing external traffic ?

  1. Internal Servers are on 192.168.x.x/16 subnets and 30 vlans with their corresponding self ip and floating ip for 30 applications are configured as internal network. Similarly 30 no of VIPs/floating ip on subnets of 172.16.x.x/16 are configured as external network (currently defined on Server Iron LBR which is going to replaced with F5).
  2. Customer having gateways of all the internal servers (192.168.x.x/16) on WAN Router and don’t want to change it. All the internal servers should be terminated on the F5 LBR through a tagged interface carrying all the VLANs for 30 different subnets/applications.
  3. VIPs/Virtual servers for all the 30 applications are to be defined on F5 LBR using 172.16.x.x/16. Clients with any source IP should be able to send request for Virtual servers network and that request should be routed through the WAN Router to the F5 LBR using P2P link via static routing.
  4. Now my understanding is that if we replace their existing LBR with F5, we have to configure an interface as external/uplink on F5 end and tag all VLANs. Same VLANs must be tagged at router/Upstream device in order to make all VLANs pass this link. But in this case we need to create 30 SVIs each per application on the upstream router as well , so that it can talk to its individual floating IP & VIPs at F5 end?
  5. If this is the case, customer does not allow creating 30 VLANs and their SVIs on their upstream router. What is our solution in this case?
  6. Can we configure P2P link between their upstream device and F5 as mentioned in point 3 and shown in attached the diagram. Thanks

 

application delivery
BIG-IP
LTM

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  • Leonardo_Souza's avatar
    Leonardo_Souza
    Icon for Cirrocumulus rankCirrocumulus
    Oct 30, 2017

    It is not a common setup, but yes you can have just a single VLAN for routing. You need one or more IPs for the WAN route, depending if a single device or not. For the F5s, you need 2 non-floating IPs, and 1 floating IP.

     

    Basically, in the WAN router you create routes to point all 30 networks to the F5 floating IP. All virtual servers should be configured to expect traffic from the routing VLAN. In that case, WAN route only needs an interface (or more) in the routing VLAN.

     

    If the servers have the default gateway to the WAN router, you need to use SNAT as well to make sure traffic returns via F5.

     

    SNAT information:

     

    https://support.f5.com/csp/article/K7820