hi.
Also i've got similar problem. beacuse IOS bugs. I couldnt find report on Cisco about it. ?I can propose you below IOS on 3750. It is really working for group function.
c3750-advipservicesk9-mz.1
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2 Layer3 Switches + VLANs Default Gateway problem
I have two layer 3 switches (3750) im using them as redundancy in my production network, where each server has two NIC (teamed) each one is connected to a switch. I have created the VLANs and assigned IP to each of them to take advantage of the Layer 3 capabilities.
the same VLAN config has been copied to the second switch.
But what I dont understand is that when I issue the IP address of the VLANs in the second switch the network stops completely and the switch keep logging a duplicate gateway errors.
Now I got the impression that its appears to be assigning IPs gateways to VLANs gateway can only happen in one switch at time, but if that first switch fail? The second switch wont be able to identify the Gateway simply because it doesnt know about, as result I left with no redundancy!
Please help understand whats Im missing.
This is the command im using:
Switch(config)#interface Vlan2
Switch(configif)#ip address 10.1.2.1 255.255.255.0
Switch(configif)#no shutdown
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Answers
Do check these links for HSRP configuration
http://itknow
htt
Che
Yasir
I understood you want to connect a host to both switch for redudancy with seperatly ethernet. In this time you need to you use group option. Some of IOS for 3750 is not working correctly with group options. if you are using one NIC yes HSRP will be enough. But 2 NIC ons server needs group option. So, Both NIC will take same ip address and three 3750 switch will be stack.
HSRP is provide switch redundancy in one ethernet, it will not support host redundany. Your main question to use both NIC card on different 3750 for redudancy. you will see below 3750 sample configuration with group option. GigabitEthernet2/0/16 is main GigabitEthernet1/0/16 is backup channel. Server 2 NICs can have same ip address.
switch 1 provision ws-c3750g-48ts
switch 2 provision ws-c3750g-48ts
!
vlan 32
name Backend_test
!
interface Port-channel16
description to_CBDEV_etherchannel
switchport access vlan 32
switchport mode access
interface GigabitEthernet1/0/16
description -= Test =-
switchport access vlan 32
switchport mode access
channel-group 16 mode on
interface GigabitEthernet2/0/16
description -= Test =-
switchport access vlan 32
switchport mode access
!
What I interpreted him wanting to do is:
1) Server with two NIC's. NIC1 goes to SW1 and NIC2 goes to SW2.
2) Server is configured with NIC teaming, so that if either NIC fails, server will still be up.
3) SW1 and SW2 are configured so that if either SW fails, network will still be somewhat usable.
4) SW1 and SW2 are L2/L3 switches and he wants them to back either other up as the defualt router VLANs.
If I am right, then HSRP is a must on the switches.
The servers can be configured with NIC teaming, one NIC will be used for all inbound traffic, both for all outbound if you configure the team as active/active.
Since it appears there are only single connections between the switches and the servers, no channel groups needed.
giltj you are dead right, the solution has worked for me, i created HSRP virtual IP to each VLAN gateway, i tested it, i took out the trunk port between the switches, and i can see the backup switch takes over and become active, and when i connected it back the failover back to the primary Switch.
however this type of failover is not stateful, i mean when i tested it using ping i can see some timed out packets during the taking over process , so there is a high possibility to loss sessions.
Yasir: im reading thru your materials, very useful, thanks.
equalizer: you solution interesting and i think thats what im going to do next.
You may want to be careful when implementing equalizer's solution. Using NIC teaming to a single switch is great if you need more bandwidth (as you get more inbound as well as outbound bandwidth). It will also protect you from a NIC failure on the server, a single port failure on the switch, or a patch cable failure between the switch and the server, but it will not protect you from a switch failure.
However, one NIC to different switches protects you from all of the above and from a switch failure, however going to two different switches does not increase inbound bandwidth to the server.
Only you can decide if you need the extra bandwidth inbound more than you may want to protect yourself from a switch failure.
Yes, but you said that you were going to look at equalizer's solution. His solution is to put both NIC's onto the same switch. I was just pointing out that you get extra bandwidth, but you loose some redundency with that setup.
For stacking you can read:
http://www.cisco.com/en/US
http://www.cisco.com/en/US
However stacking requires special cables, I don't remember the exact price, but I think it is close to USD$200 per cable. You need N+1 cables for a stack, where N is the number of 3750's you have in the stack.
Dear szwy;
Stack case is not compilacted solution. It will make your task more an more easy. You just need to connect two switch with stack cable.
You don't need HSRP configuration and you can put 2 NIC on switch with group configuration. All your problem will finish. It is excatly network recomended solution for redundany task.
Dear Giltr;
I never said both NIC will be on switches. Why i dont know but everybody just consantrated to HSRP. From the begining i am trying to show more reliable and easy way for redundany. Please look my example configuration. it excatly stack-different port-group options.
Yeah In my opinion its probably best and easiest to stack the switches. All you need is to plug the stackwise cable into the back of each switch and it will automatically suck the configuration onto the new switch (The should have the same IOS version to stack). The two switches then act as one switch with the same configuration. Therefore if you plug one of the servers teamed nics into switch A and one into Switch B everything will be redundant and work properly. However you will need a connection to each switch to the router so internet will stay up if one switch failes. Not sure what kind of router you are using but if it supports fast etherchannel you could then make a etherchannel group on a port on the first switch and a port on the second switch. This will make the 2 ports act as on with load balancing and failover.
Stacking will also give you way fast throughput between the two switches. I think something like 32 Gbps.
I was thinking of using the stack to eliminate the need for using hsrp as they have the same config and it would also ease managment as you are managing 1 switch config instead of 2 switch configs. It will also provied a faster backplane between the two switches.
I was just throwing out another option instead of HSRP.
stack looks like what i need but i don't think there is enough budget, however i will let the management know, anyway, i think there is routing problem in my network after i have implemented the HSRP.
for instance when i issue tracert command from VLAN to another i got the assigned VLAN gateway not the required Virtual Gateway.
i will send my config of the both switches please advice
thanks in advance.
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by: giltjrPosted on 2009-01-17 at 13:01:26ID: 23402441
Are you putting the same IP address on both switches? If so, this is wrong, you can't do that. What you want to do is configure them for HSRP. On the switch you want to be primary issue the commands:
config t
int vlan2
ip address 10.1.2.2 255.255.255.0
standby 1 ip 10.1.2.1
standby 1 priority 110
standby 1 preempt
On the switch you want to be standby/secondary:
config t
int vlan2
ip address 10.1.2.3 255.255.255.0
standby 1 ip 10.1.2.1
standby 1 preempt
This assumes that 10.1.2.2 and 10.1.2.3 are not in use. If they are already in use, you need to pick two other IP addresses.
For more info read:
http://www.cisco.com/en/US