Self IP and Virtual IP

[Venkata_Narayan]

Hi,

Like to know about the relationship between self ip and the virtual ip in F5? Of course I did read the article (https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/tmos-routing-administration-11-6...) but our F5 version in on 12 and I am unable deduce how these two elements work/communicate. Can you kindly help me to explain me on this.

[Simon_Blakely]

relationship between self ip and the virtual ip in F5?

The self-IP defines the IP address range of the associated VLAN.

Virtual IPs (addresses) should be in the same IP address space as specified by the self-ip/vlan.

This means that the Virtual Addresses share the MAC address of the (floating) self-IP, and this is the MAC address sent out when the LTM sends Gratuitous ARPs for Virtual Addresses after going Active.

You can create Virtual Addresses that are not in the self-IP address space of the VLAN. You need to provide explicit routing for the Virtual Address to the self-IP in this case.

Also, the LTM will not send Gratuitous ARPs for such Virtual IPs after going Active - this may cause traffic issues when failover occurs.

[Surgeon]

If you had a chance to work with routers or multilayer switches then self-ip address is analog of ip address of SVI interface.

Loopback IP is similar to VIP IP (it is very rough though). But on big-ip self-ip and VIP ip share the same MAC of the VLAN they belong to.

VIP is dataplane

self-ip is sort of control plane

All service traffic goes via virtual IPs only. Device control traffic goes via self-ips only.

I hope that make sense. If not, please provide more details what you are looking for.