Cisco Switching/Routing :: How To Change Master Switch In 3750 Stack
Oct 18, 2012
We have 2 3750 24 port fiber switches in a stack and we would like to change the member to become the master. Both are running the same IOS and they are alive on the network. I read that you can change the who becomes the master by setting the priority number higher on the member, which we did. However this requires a reboot of the member to take effect. Is there a way to force this without having to reboot? One other note, both switches in stack have a single gig connection that goes to the core (6500). One gig link is blocked due to spanning-tree and this is on the member that we want to become the master.
I would like to know if it's possible to change a master in a 3750 stack without rebooting it?I searched in Cisco documentation, in the forum, and I googled it but I didn't find anything.
We have a stack of a 3750E with a 3750X, when we turn off the master, a disconnection occurs for around one minute while only one request timeout is seen when the slave is turned off. Is this normal? Details: in other words, when the slave switch is elected as the new master all the port-channels and some physical ports become in 'down' state before reobtaining the up state again, this results in a one minute outage. The question is: is it normal to have a layer2 control traffic interruption when the master fails and re-election occurs and if yes, what is the normal downtime in seconds. the layer2 control information such as port-channels LACP protocol are not synchronised to all slave switches by the master?
I have two like switches in a stack (WS-C3750G-48PS 15.0(1)SE2 C3750-IPBASEK9-M). Switch#1 is the master and is the one that needs to be replaced. Can I force Switch #2 to be the master, then power down switch#1, remove switch#1, insert the replacement, and then power on the newly added switch without shutting down or rebooting switch#2?
I have a stack of 2960S (c2960s-universalk9-mz.122-55.SE2.bin) and the master has failed (used to have a priority of 14). The second switch has become master (priority 1) as can be seen below: [code]
If I connect a new blank 2960S (same IOS) through the stack ports, will the master sync its config to the new one without causing problems?As I understand the new blank switch will also have a priority of 1 and will by default be numbered as 1. So if the config is correctly synced and I later on want to make switch 1 the master, I need to set the priority: [code]
We currently have as our stack master a 24 port Non-PoE that we want to replace with a 48 port Non-PoE. The 48 port switch at one time was provisioned as switch 3 in the stack (not the master). Correct me if I am wrong, but theoretically all I should need to do to get this working is to shut off the existing master so it re-elects a master and then provision the 48 port switch as the new switch one and make sure switch 1 has a high priority?
Do I need to write erase the switch that is replacing the current master first?
I've got a 3750 stack with a 3750-48p being switch 1 and a 3750-12s being switch 2 and switch 2 is the master. I would like to change the stack member numbers. I would like the 3750-12s to be switch 1 and the 3750-48p to be switch 2. I undertand I will have to reboot the stack for the change to take affect but here are my questions: How would this change affect the stack running-config ? will the switchport config follow the change ?
End user have had problem with IP phones that are connected to 3750 stack; many times IP phones lose connection with CallManager and the only way to clear this issue is with clear arp command. DHCP for IP phones is configured in 3750 stack.
At the beginning 3750 stack was set a VTP server, and the others as VTP clients, we detected another VTP server switch so we thought that was the problem, but after removing the issue remains. Finally we set all switch in transparent mode.
Base on this we decided to change the software image 12.2(35)SE1 C3750-ADVIPSERVICESK ---> 122-53.SE2 IPSERVICES I'm going to follow the procedure 3750 Series Switch Stack IOS Upgrade − Automatic .
as it show in the following information there are 4 differents models of 3750 switches, I have already download c3750-ipservicesk9-tar.122-53.SE2.tar for 3750G-24TS.
I have two doubts:
1. There is no problem for using this tar file for all models?
2. I followig command is correct for the change I plann to do ?
i want to remove an access layer 3750 48 POE master switch and replace with a new 3750 switch in the stack. i want to copy the same configuration to new switch since the old switch is having POE issue and I got replacement of the malfunctioned switch. we have VTP domain is configured in the network...
I configured 3750 A switch with vlan 20 and its IP address 192.168.20.41Its default gateway was 192.168.20.3Then i configured 3750 B switch with same default gateway and vlan 20 IP 192.168.20.43My question is now when we stack it becomes single switch and now vlan 20 ip address is 192.168.20.43 thats only IP i can see.So how does stack switch choose vlan 20 IP?Does it choose highest IP address between two switches if they have same vlan 20 as in my case?Also when i go to switch 3750 b by session command and do sh ip route it does not show ip default gateway .Also it shows vlan 20 as admin down .
We have a stack of 3 cisco swithes 3750s WS-C3750G-24TS 12.2(25)SEB4 .We plan to recover a switch from the stack as it is not needed any more The switch we plan to recover is the existing Master.If we change the priority (switch 1 priority) and make another switch the master using command line will we have any loss of connectivity to the servers conecting to the stack ?
We have a WS-C3750G-24PS switch running 12.2(50)SE , C3750-IPBASEK9-M in production & stand alone and we want to ask a new Cisco WS-C3750-24P running 12.2(55)SE3 , C3750-IPBASEK9-M into the stack with the 1st one.
Just want to know if it is possible and are there any problems with the IOS being different version.
I have a stack with a lot of stack-port changes, but on all the ports, how can I determine the faulty switch in the stack, cables are already verified. We did also a restart of the whole stack power off/on
running version
WS-C3750-48P 12.2(55)SE C3750-IPBASEK9-M
This is the output after 6weeks
Switch#/ Stack Neighbor Cable Link Link Sync # In Port# Port Length OK Active OK Changes Loopback Status To LinkOK -------- ------ -------- -------- ---- ------ ---- --------- -------- 1/1 OK 4 1
In the current set up I have a LAN stack of 5 3750 switches configured as an access stack. As per the requirement I need to partition the current 5 switch stack into two individual stacks of 3 & 2 switches respectively. Kindly let me know the step by step process withh all the necessary commands, reloads and reconnections. I purpose to do it by changing the priority of current member switch to 15 so that its elected as Master in the new partitioned switch stack. But not sure what all steps required and in which order.
One switch of our stack of 8 3750 have reboot with no reason. Nobody was in the room server when it appears et there was'nt any electrical problem at this moment.
I have four-switch Cat 3750 stack that has been working reliably for a couple years. Suddenly the other morning it reboots itself, and has been doing so every 24 hours since. take a look at the attached log? This should really be a Smartnet thing, but as it turns out the warranty we have on this is not Smartnet .
We are having 3750 Stack switch as our edge switch. Here we are having some issues as low memory & itermediate High CPU utilization.For memory when we checked its shwoing maximum memory is allocated to DHCPD receive & ARP Input as follows
Processor Pool Total: 70829380 Used: 56809532 Free: 14019848 I/O Pool Total: 12582912 Used: 8554920 Free: 4027992 Driver te Pool Total: 1048576 Used: 40 Free: 1048536
[code].....
i want to understand why this 2 proceses (DHCPD & ARP input) taking more memory?High CPU: We also facing intermediate high CPU utilization (above 95%). When CPU is high there were 2 processes consuming more CPU are 'Spanning Tree' (about 20%) & ARP Input (about 66%). we also checked the ARP entries, there were 1500 ARP entries & 2 incomplete ARP (out of 6000 ARP supported)
At a customer i've tried to add a new 3750 switch til a running stack.I used the following proccess:
1. connect stack cables to the new switch
2. bootup new switch.
Normally the new switch will become a member of the stack, but here, the switch says its the stack master. I can see that the stack port from the old switches connecting the new is up.The only way i could make it work was to provisioning the new switch as switch nr x, save, power off and then connect it and boot it up.The IOS i the same on all switches.
in our network we were using three 3750-48-s switches with stacking one of the switch due to some hardware failure power problem,
now i want to add a new switch 3750-48-s in the existing Stack two switches , the old two switches ios version is = 12.2(25r)SEC the new Catalyst 3750 io verion is = 12.2(35)SE5
how to add this switch in the existing two stack switches , with documentation
I have stack of 2 switches 3750?I config etherchannel between them.
here is result
2 Po2(SD) LACP Fa1/0/15(I) Fa2/0/15(I)
Both ports are up up but standalone Int port channel 2 is down down.Need to know if this is default behaviour when we config etherchannel between stack switches?
is there a document that explains the compatibility of 3750 series that can be stacked together? for example can we stack 3750-x with 3750-v2 without the power sharing? Can we stack a L3 3750 with L2 3750 without upgrading the L2 switch IOS to ip services?
We have a live stack with 4 Cat 3750 switches of mixed varieties. Switch 1 crashed the other day and didn't come back up. A power reset brought the switch online again, and switch 2 is now running as the stack master. We are going to replace switch 1 in a staged approach to minimise client downtime. Switch 1 is a ws-c3750-48ts and we will be replacing it with a ws-c3750g-48ts. I will be pre-provisioning and installing the new switch into the stack as switch 5 and configuing the ports to be the same as switch 1. The cables will then be moved over from switch 1 to switch 5 so the changeover time should be minimal. When all cutover, I'll power down switch 1, reconfigure the stack cables and remove switch 1 from the stack.
My question is to what occurs next. If I perform a 'no switch 1 provision ws-c3750-48ts' will I be left with switch 2 through to 5 (ie no switch 1)? I can live with this moving forward. I know I can renumber switch 5 to be switch 1 if I want, but my understanding is that I have to reload the member switch which is something I'd like to avoid at this stage. In my reading, I saw the statement - "Note: You cannot use the switch current-stack-member-number renumber new-stack-member-number global configuration command on a provisioned switch. If you do, the command is rejected." I'm a bit confused by this statement, I'm assuming that it is saying that if I do as above but don't issue the 'no switch 1 provision' command, I cannot renumber switch 5 to switch 1 but as long as I use the 'no switch 1 provision' command first, I can renumber switch 5 to switch 1? Will all of my switch 5 port configuration information and any associated references (eg port-channel configuration etc) be changed from gi5/0/x to gi1/0/x if I do renumber?
I have looked on notes to add a switch to an existing stack and haven’t identified answers on how the IOS will be affected on the new switch – will it downgrade to the current stack version or will the current stack upgrade to its version. At this moment in time I would prefer if the new switch IOS downgraded to the current stack IOS version.The new switch is a 3750V2 – will this affect how it joins the stack?The new switch has the image of IPBASEK9-M – again will this affect how it joins the stack?
I have a Cisco 3750G-48PS Running IOS 12.2(40) and was wondering how many physical ports are supported in an LACP Configuration. Is it 4 or 8 ports in a single switch.
If I have a dual 3750 stacked together, and I want to configure (8) port LACP, Can I take (4) ports from each switch in the stack and LACP together.
I have been looking at the Cisco Hardware docs and I can't find anything on the proper way to setup a 2 switch stack for Stackwise redundancy and Stackpower redundancy. Everything details 3 or more switches.
I have 4 switches in a 3750-X stack.Here is the output from the stack why are the switches out of order and I'm not able to bring up switch 1 port 1.
switch 4 port 2 shows not connect it is I've checked the cables.
Power stack name: Powerstack-4 Stack mode: Power sharing Switch 1: Power budget: 695 Low port priority value: 22 High port priority value: 13 Switch priority value: 4 Port 1 status: Shut Port 2 status: Connected Neighbor on port 1: 0000.0000.0000 Neighbor on port 2: c471.fe84.e100
Switch 2: Power budget: 713 Low port priority value: 21 High port priority value: 12 Switch priority value: 3 Port 1 status: Connected Port 2 status: Connected Neighbor on port 1: c471.fe85.3000 Neighbor on port 2: c471.fe80.2800
Switch 4: Power budget: 697 Low port priority value: 19 High port priority value: 10 Switch priority value: 1 Port 1 status: Connected Port 2 status: Not connected Neighbor on port 1: c471.fe80.2800 Neighbor on port 2: 0000.0000.0000
Switch 3: Power budget: 710 Low port priority value: 20 High port priority value: 11 Switch priority value: 2 Port 1 status: Connected Port 2 status: Connected Neighbor on port 1: c471.fe84.e100 Neighbor on port 2: c471.fe7f.eb00s
I am attempting to add and Catalyst 3750 - 12 port Gigabit switch to an existing stack of 3750 48 port switches (non-X fabric). I am not sure how to proceed. These are the two questions/thoughts I have. Any additional perspective I should have before proceeding.
What kind of configuration should I apply to the Gig switch before adding it to the stack?I am sure I will need to assign priority to the new switch, ideally, it will act as master.
I have used stack wise 3750 for a long time. Now,I have a new stack of 3750. Both of them are trunking together. If I have a VACL running in the old stack, do I need also implement in the new one.
I'm looking at the possibility of purchasing a few 3750 to build a switch stack to replace my current core and access switches. I'd like for the stack to support server, SAN, and user traffic, as well as provide simple switch management, redundancy, and failover. I've also been looking at the 4500, 6500, and Nexus series switches (although the Nexus switches maybe a bit too much for my network).
My current environment consists of 3560's as the core/distribution/access switches, a mixture of Hyper-V and VMWare environments (although we're slowly migrating to Hyper-V), an HP SAN (P4500), and about 100 users. Any issues going with the 3750's or have an alternative, more efficient solution?
