how can i have multiple subnet from same vlan

[Mk25]

hi,

how can i have these subnets in same VLAN.

Network Address              Usable Host Range                          Broadcast Address:
172.17.221.0                 172.17.221.1 - 172.17.221.2               172.17.221.3
172.17.221.4                172.17.221.5 - 172.17.221.6              172.17.221.7
172.17.221.8                172.17.221.9 - 172.17.221.10              172.17.221.11
172.17.221.12               172.17.221.13 - 172.17.221.14           172.17.221.15

[balaji.bandi · Accepted solution]

what is the reason to be in the same VLAN, if all same VLAN, why not have a single subnet?

[GVD]

configure subnet 172.17.221.0/28 on the SVI

[Joseph W. Doherty]

"configure subnet 172.17.221.0/28 on the SVI"

Nooooo.

If you do that, subnet broadcast addresses .3, .7 and .11 become host addresses as well as network addresses .4, .8 and .12 become host addresses too.

Further all hosts would consider the other subnets' IPs to be in its own subnet rather than external networks.

Don't confuse the summary address covering those subnets the same as a subnet address on an SVI rather than the distinct subnets.

[Joseph W. Doherty]

Yes.

On the SVI configure one of those subnets as the primary and the others as secondaries.

Doing this, though, does raise some issues, such as a full broadcast (not a network broadcast) will be seen by all hosts or if host don't have a gateway configured, they won't initially send traffic to it.  Also, some routing protocols and support services work (or not work) with secondaries.