HSRP: ADDING NEW VLAN


LIVE SCENARIO EXAMPLE

STEP 1

Simply create the vlan

Int vlan

Ip address <>


STEP 2

Newly created vlan has to be incorporated in HSRP too. Analyze design in your network.

Two types of design

FIRST TYPE

Single vlan : Single vip : Single group

SECOND TYPE

Multiple vlan’s : Multiple vip’s : Single group

EXAMPLE

showing both type of combined designs

A#sh standby br

Interface   Grp Prio P State   Active         Standby         Virtual IP

Vl1         12 200 P Active   local           10.25.34.12     10.25.34.1

Vl15       15 200 P Active   local           10.25.34.131   10.25.34.129

Vl20       20 200 P Active   local           10.25.35.67     10.25.35.65

Vl110       12 200 P Active   local           10.25.32.12     10.25.32.1

Vl111       111 200 P Active   local           10.25.34.243   10.25.34.241

Vl112       12 200 P Active   local           194.181.40.12   194.181.40.1

Vl150      14 200 P Active   local           10.25.36.12     10.25.36.1

Vl190       12 200 P Active   local           10.25.36.131   10.25.36.129

Vl191       12 200 P Active   local           10.25.36.195   10.25.36.193

 

FIRST TYPE

Here, Vlan 1, vlan110, vlan112, vlan190 all are load shared using same group, HSRP group number 12.

SECOND TYPE

Whereas, all other vlan’s have one to one mapping, different group for different vlan.

You need to decide, new vlan will be utilized with which type of design from above?


 

STEP 3 

For HSRP to work properly, we need to have Layer 2 connectivity between HSRP members.

Over the Layer 2 connectivity, we need to allow newly created vlan, to avoid HSRP dual active scenario.

To confirm Layer two connectivity, below is the example

 

FIRST

Get mac address using “sh ip arp”

SECONDLY

Use Layer 2 traceroute

In below command, put source & destination mac captured from above arp command output.

ROUTERA#traceroute mac  000e.d79c.67ff  000e.d79c.67ff  vlan 1

Source 000e.d79c.67ff found on ROUTERA

ROUTERA (10.25.34.11) : Po1 => Po1

Destination 000e.d79c.67ff found on ROUTERA

Layer2 trace completed.

 

 

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2 comments

  1. Hi Mr. Sharma,

    Could you please elaborate “Dual Active” scenario. Also let me know the Mac address that you have taken is of Vlan X (X= New vlan) and what is the necessity of doing Layer 2 traceroute.

    Like

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