We have 3 sites, each sites having 28 servers , 10 3550 swittches and 2 3750 switches.
Each server has 2 NIC cards. There are 2 Vlans, each server belong to different VLAN. Each VLAN port of server is directly connected to 3550 switches in order to connect it to IP network. These 3550 switches are in turn connected to 2 redundant 3750 switches.
To route the traffic from a site to another, the 3750 switches are running at L3 using HSRP and EIGRP. For intra-site communication, our 3550 switches and customer 3750 are running at L2 using standard Spanning Tree 802.1D
In each site two 3750 switches are root bridges of VLAN1 and VLAN2
Because of std STP the convegence time is too high around 50 seconds , and its causing problems in the server and database synchonisation.
The possible solutions we have is:- RSTP and enabling uplink fast on 3550 switch.
We can do this only in one site at a time.
Please help me in the following:-
1) What are the risks and conseqences whilie impleneting RSTP and uplink fast.
2)Which of the 2 solutions is better or any better solutions, and how can we implement this, without causing any outage?
2) Make sure that, all the trunk ports of 3550 and 3750 switches are operating in Full duplex mode. Or do i have issue the command to force the port as point-to point link, ie "spanning-tree link-type point-to-point" ? Which is the safest option?
By making sure they are full duplex the switch should see them as P2P links.
Please confirm if this proceedure is correct? Usually how long will it take for the RSTP to recalculate parameters and attain stability assuming that there is no topology changes? Anyways am going to request the customer for 1 hour maintenance window.
Procedure looks fine to me. To be honest, assuming you don't have to reload switches, we are talking minutes for it reconverge to a stable network. I suggested an hour because you just never know what might happen and not necessarily with STP ie. you may reload a switch and it does not come up correctly etc. I am not trying to worry you but it's always best to plan for all eventualities.
To enable uplinkfast in all the 10 switches , i have to issue the command "spanning-tree uplinkfast" in global configuration mode right? (or i have to issue the command in interface level?). I have already enabled "portfast" in access ports fo 3550 switches that is connected to the servers. Does Enabling "uplinkfast" requires it to be changed or i leave it alone? I feel it shouldnt be changed, but still i want to make sure.
You should enable in global config mode. You should leave portfast configured ports as they are. You obviously don't want portfast configured on the switch uplinks.
To implement uplinkfast If i issue the command "spanning-tree uplinkfast" in all 10 switches one after another, how long will it take the network to be stable?
Again, if there are any STP calculations we are talking minutes at most for it to reconverge.
Most probably customer is going to agree only for UPLINKFAST.
If you are going to be getting an outage anyway, and outages are not that easy to come by, i would strongly recommend you advise the customer to go with RSTP and not just uplinkfast. RSTP is a great improvement on STP and not just because it incorporates uplinkfast. If all your switches support it there is no reason not to migrate to it.
BTW its good to know you were a Solaris admin, I am also from the same domain specializng on SUN hardware and Solaris.
I still miss working on Solaris sometimes but i suspect if i was put in front of a Solaris server now i wouldn't haven't a clue what to do