MSTP with VLAN configuration Help

[Usaia Tawakevou]

I want to implement MSTP on my network. Attach herewith is what I want to achieve. Currently I have all the fiber connections connected to the HP4204vl at the Server Room 1. The HP4204vl in server room 1 is the core switch and doing inter-vlan routing. I have implemented 7 VLANâ s. I have statically defined on a switch all the 7 VLANs that might use that switch and those VLANs tagged on the links between the switches. Switches I have on my environment ranges from 4204vl,2610,2810, 2824, 2524,2510
My plan is to configure 2 x 2900 and stacked them. Make the HP4204vl as the root switch and the stacked 2900 as the root backup and the backup router for the HP4204vl
All the 2524â s will be replaced by the 2510â s. I just need configuration help with:
â ¢Making the 4204vl in server room 1 as the root switch
â ¢Making the stacked 2900 as the backup root switch and backup inter-vlan router
â ¢Ensure that my network traffic (7 VLANâ s) always has a valid path through the redundant link during a failure of a link or switch â Will sort out the connections without redundant links later
Hope someone helps

[Shadow13]

Just a quick point, stackin in HP is for management only, they will not act as 1 switch so i think it will not achieve what you require, if you implement it like this only 1 2900 will be the backup.

2nd thing is taht the 4200 series and the 2900 series are not supporting VRRP which is required to do the master and backup routing devices.

[Usaia Tawakevou]

Thanks for the information. So I guess I will just have to use 1 2900 as my backup. Do I have to configure any MSTP configuration on my edge switches or they are just done from the 2 root and backup. Any configuration example would really help.

Thanks for your help

[Jaap Laaij]

Hi Usaia,

Looking at your drawing a simple "span" command will do and setting the priority.
Only the switches with the redundant paths will need spanning-tree.
In your case only CST (=RSTP) will be used.
Or for simplicity you could fore RSTP-mode.
All VLANs will take the same route.
It is a shame you don't have connections from the edge switches towards serverroom 2.
Then you could use MSTP as it should. However you would need VRRP which needs the Premium license.

I quess the connection between the 4204 and the 2900 is not redundant?

Greetz Jaap

[Usaia Tawakevou]

Thanks Jaap. We will start off with what we have at hand at the moment and will move to other redundant links setup later.

Thanks for your advice

[Usaia Tawakevou]

Jaap, on another note, I notice that on the manual it says that 4200vl switches support MSTP only. So I believe I have no other choice.

My plan is this:
Create Instance 1 with VLAN 1-7
Create Instance 2 with VLAN 1-7

Then configure 4204vl:
- Root for Instance 1
- Backup for Instance 2
- Root for the IST

And configure 2900:
- Backup for Instance 1
- Root for Instance 2
- Backup for the IST

4204vl:
--------
4204vl(config)#span priority 0
4204vl(config)#span instance 1 vlan 1-7
4204vl(config)#span instance 1 priority 0
4204vl(config)#span instance 2 vlan 1-7
4204vl(config)#span instance 2 priority 1
4204vl(config)#span ***enabling Spanning Tree**


2900:
--------
2900(config)#span priority 1
2900(config)#span instance 1 vlan 1
2900(config)#span instance 1 priority 1
2900(config)#span instance 2 vlan 2-3
2900(config)#span instance 2 priority 0
2900(config)#span ***enabling Spanning Tree**

Is this how I'm going to configure my 2 switches

What configuration will I do for the edge switches with redundant link ? same as the above ?

Need configuration help

[Jaap Laaij]

Hi Usaia,

You can use RSTP. Read e.g. page 6-14 and on in the Advanced Traffic Management guide.
You will also need VRRP if you want to make a switch the backup root switch.
VRRP will allow the use of a 'shared' default gateway IP-address between two core switches. This is necessary for your pc's if one of the two core switches fails.
To be able to use VRRP you will need to buy a Premium license for both core switches.
Neither the 4204vl nor the 2900 switches supports the VRRP feature.

Greetz Jaap

[Usaia Tawakevou]

Hi Jaap,

The manual says nothing about 4204vl RSTP on that page that. For the time being I can go without VRRP. My current concern is if one of the link breaks to one of the site, other sites (that have the redundant link) suppose to find an alternative way back. Does that still require VRRP ?

[Jaap Laaij]

Hi Usaia,

Unfortunately your right. RSTP in that manual only applies to every model except the 4204 :(. Read over the chapter headings. Sorry..

MSTP requires: configuration name, configuration revision, MST instances and mapped vlans on all switches to be the same. That is not the case in your config.
You need VRRP with MSTP because - if one of the core switches fails the other will take over for the instance it is the backup for. However that switch has another IP address for the VLANs mapped for that instance. That means the configured default gateway on the pc's will be misconfigured. That will not be a problem if traffic remains within a VLAN but will be for hopping over to another VLAN.
That's where VRRP comes in. It enables the core switches to have one virtual ip-addres for each VLAN within the instance. If one of the cor switches fails the virtual ip addres is used by the other core switch.
You could also decide not to implement MSTP instances. Then MSTP will work like rstp with 'normal' spanning tree operation.

Hth Jaap

[Usaia Tawakevou]

Thanks Jaap. Shadow on his respond says that 4204vl and 2900 doesn't support VRRP. RSTP is not supported by 4204vl that means Im left with STP (802.1D) :)

My main concern here is creating another path for a site to be able to connect back to the server room if the main path fails. At the moment I have alternative fiber/UTP links setup but not connected. Wireless bridge is something I'm planning to link server room 1 and server room 2. This will come in when I first get the current infrastructure works with redundant paths. Switch failure issue can be addressed by replacing the switch itself as I got a couple of spares with me.

Any other idea or option I can use ? Hope I'm clear and thanks for your help and response