3750 stacking questions (2)

My first questin has to do with the Console port in a stack. It has been observed that the console port on the master switch is designated "Con 0". So my question is how do I access the other con ports on member switches to configure them?
The second question is what is the mechanism for statically numbering all of the switches in a stack so they are always numbered the way I configure them to be ie in case of some disaster or power outage I need to know that switch 5 will come back as switch 5 even if switches 1-4 do not come back to life.
Thanks

1. When you connect via a console cable to any of the switches in a stack you always access the stack master. The stack master is the only switch that can be used to configure the stack and its members. Assuming you have a stack of two 48 port (10/100/1000) switches; switch 1 is the master and switch 2 is a stack member. If you want to configure ports on switch2 you just use the appropriate port numbers (int gig 2/0/1 to 2/0/52). If for some reason you need console access to a stack member you can use the 'session ' command; however, do keep in mind that this access will be limited to only show and debug commands. All configuration is done via the stack master.
2. You can renumber a switch to ensure that it always retains the same number by using the 'stack renumber ' command. For example to renumber switch 2 in a stack to 3 you will use 'switch 2 renumber 3' global configuration command.
The following URL has great information on how to manage switch stacks.
http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_guide_chapter09186a008050245f.html#wp1170757

Similar Messages

Question Re: connecting 2960C switch to 3750 stack, max number of VLANS limit...

Hypothetical question: Let's suppose for example I've got a 3750 switch stack in a data center with over 300 VLANs defined on the 3750 stack, and that stack is also my VTP domain server. I wish to connect a small compact 2960C switch (which has a max limit of 255 VLIDs) as a VTP client to the 3750 stack's VTP domain and have the port at each end of this uplink connection set up to be an 802.1q trunk, but limit the VLIDs trunked to the 2960 to just a small handful (let's say just 3 or 4 vlans) via for example something like "switchport trunk allowed vlan 1,2,11,18" on the uplink port of the 2960C switch. Will the mere fact that there are hundreds of VLIDs present in the vlan configs on the 3750 stack confuse the little 2960C switch's max 255 vlans limits? Or will the 2960C with its "Lan Base" software happily show all 300+ vlans present in the parent switch stack in a "show vlan" command but simply only let you activate up to the 255 limit locally on that switch?
Normally I'd just use a 3560C switch with IP Base software for this purpose and not worry about any vlan max limit, but we're having to penny-pinch the project and save a few hundred dollars on this compact switch purchase and I've never used the 2960 family before. The small compact switch will be used to host a non-Cisco, 3rd party wireless LAN controller with several APs that will have a handful of different SSIDS, each on a separate vlan, and will not be located in the data center, but in another building connected by a fiberoptic link that will carry the "trunk".
EDIT: I found an old discussion thread where someone else was faced with a similar scenario, and he discovered that even with using "switchport trunk allowed..." and "switchport trunk pruning..." commands on the interfaces at both ends of the link, that the 2960 switch would still fall out of VTP client mode into transparent mode, which make you lose the benefit of having centralized management of a VTP domain. Seems the VTP protocol will always publish the full list of vlans from the server and this blows the mind of the small switches which drop into VTP transparent mode because they cannot handle all that many spanning tree sessions. Looks like the 2960 simply cannot be used in a high-vlan-density network if you wish to preserve central VTP domain management features. Rats.

The house network machine can browse and playback/stream video fine, however at the same time the machine on the wireless shows significant slowdown when browsing the web.
The issue is defiantly on the wireless side, If i plug a machine directly into the switch and assign it a static ip, i do not get slowdown, so this is happening before it reaches the poe switch.
So many factors affect the way to stream data up and down wireless. Sure, I have seen >40 clients on 802.11a AND 802.11b radio of a single 1140 AP. But this is not good. Why? Because wireless is a very "noisy" environment. When one talks, everyone else has to stop, listen and waits for their turn. The > 80 wireless clients connected to the 1140 AP had a detected maximum speed of 11 Mbps and they couldn't get any higher than that. They couldn't get any lower than 11 Mbps because I've disabled lower data rates.
You said you hard-code the channels to 1, 6 and 11 but what is the co-channel interferrence like in your wireless environment?

Up-link 2 x 3750 Stack to 4 x 3850 stack

All -
Sorry is this is a rather simple question but I’ve never worked with Stack switches before? I have a remote office that has 3 floors. On one floor we have a 2 3750s in a stack. On another we have a single 3560 and I’m going to be installing a new 3850 stack – the new stack will have 4 x 3850’s...
My question is how should I uplink the other switches to the new stack? In the new stack I have a master a slave and two member switches. Should I create a port channel from the 3750’s and use all available links and spread them across all switches in the new stack, and then do the same with the single switch on the other floor? Or should I create two port-channels from the 3750 and the 3560 to the new 3850 stack?
My thought is that if I create a single port channel form each switch to the new stack I would be basically be removing spanning tree from the environment and basically daisy chaining the switches? Is this a valid solution? Also does the stack act like a chassis where the control plan would be on the master – if so can I spread a interfaces in a port channel across all members in the stack?
Thanks in advance
Mike

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To take advantage of fewest (logical) devices and redundancy, run a dual Etherchannel from your new 3850 to the 3750 stack and the 3650. On both the 3850 and 3750 stacks, insure the same Etherchannel links are on different stack members.
Logically, you would no longer need STP, but keep in running in case anyone accidentally creates a L2 loop.
As to what stack members to terminate uplinks/downlinks on, on 3750s, Cisco recommends avoiding the stack master (not possible on your dual 3750 stack). I don't know what Cisco's recommendations, if any, is for 3850 stacks.
Yes, stacks "appear" much like chassis devices, i.e. stack member ports "appear" like chassis line cards ports.

Magic number mismatch: bad mzip file in 3750 stack switch

Hi All can anybody help me in this error msg
"magic number mismatch: bad mzip file"
I am trying to upgrade the switch with"c3750e-ipbasek9-tar.122-55.SE5.tar" in 3750 stack switch it is showing this error msg while booting
thanks in advance

Hi,
The reason you are getting this error message on the switch is a corrupt or wrong IOS image "c3750e-ipbasek9-tar.122-55.SE5.tar".
If the switch is in rommon mode, and you have any other image in the switch, boot it using that image. Once the switch is up, download and copy the correct IOS image once again on the switch and try to upgrade.
If you need help in finding the correct IOS image, give me the exact switch model number, i will help you with that.
But forsure the image is wrong or corrupt and that is why you are getting this error.
Thanks
Ankur
"Please rate the post if found useful"

Re: Cat 3750 Stack Management

Hello,
I am building a few 3750 stacks with three or more units, I want to be able to poll/monitor each individual switch in the stack but as it only has 1 ip associated with the stack, how can I do this? I am blind to a switch going down in the middle of the stack. I saw this in a four-year-old forum, but I say no specific resolution.

All stack management happens through the commander. The stack looks like a huge switch. If you want to monitor a specific switch's interfaces you can. They will be numbered as *EthernetX/0/Y, where X is the stack member number and Y is the interface number. CPU utilization can only be monitored on the active stack master, though. Inventory can be obtained from each stack member using ENTITY-MIB. Environmental data can be obtained for each switch using the CISCO-ENVMON-MIB.

Does PI 1.3 alarms when a 3750 stack member goes down?

Hi
One 3750 stack member went down but the PI 1.3 did not shown any alarm.
Connecting CLI on the stack we see the status Provisioned on the failed member.
Is any way to detect this failure?
I think it should show some alarm like Card down pointing to the failed stack member.
Any help is appreciated

Unfortunately PI 1.3 does not supports stack member down situation. There was an enhancement for this :
CSCuh81366 : PI needs an event for the loss of a stack member
You need to move your PI to version 2.0 or higher to have better stack management from PI.
-Thanks
Vinod
**Encourage Contributors. RATE Them.**

3750 stack won't sync with NTP server

Any help greatly appreciated with this one - I can't for the life of me figure out what's going wrong here.
I'm working on a 3750 stack in Singapore (UTC +8) and I'm trying to get it to sync its clock with 3.sg.pool.ntp.org.
This is the weird part - "sh ntp associations" shows that it is syncing:
address         ref clock       st   when   poll reach delay offset   disp
*~199.195.193.200 203.117.180.36   2     52     64   377 80.936 -13895. 1.771
* sys.peer, # selected, + candidate, - outlyer, x falseticker, ~ configured
And "sh ntp associations de" shows that it's happy:
199.195.193.200 configured, our_master, sane, valid, stratum 2
ref ID 203.117.180.36, time D691F63E.C4B691CD (17:26:22.768 UTC Tue Jan 28 2014)
our mode client, peer mode server, our poll intvl 64, peer poll intvl 64
root delay 196.39 msec, root disp 592.71, reach 377, sync dist 944.69
delay 80.93 msec, offset -13895.2686 msec, dispersion 2.65
precision 2**20, version 4
org time D691FA8F.5FF29003 (17:44:47.374 UTC Tue Jan 28 2014)
rec time D691FA9D.5041E9C7 (17:45:01.313 UTC Tue Jan 28 2014)
xmt time D691FA9D.3B3524C8 (17:45:01.231 UTC Tue Jan 28 2014)
filtdelay =    82.20   80.93   82.17   81.49 155.78   81.08   84.67   82.09
filtoffset = -13897. -13895. -13899. -13900. -13901. -13872. -13876. -13876.
filterror =     0.00    0.99    1.98    2.94    3.94    4.92    5.87    6.81
minpoll = 6, maxpoll = 10
But the clock is stubbornly remaining unsynchronised ("sh ntp st"):
Clock is unsynchronized, stratum 16, reference is 199.195.193.20
nominal freq is 119.2092 Hz, actual freq is 119.2092 Hz, precision is 2**17
reference time is 00000000.00000000 (08:00:00.000 UTC Mon Jan 1 1900)
clock offset is -13895.2686 msec, root delay is 0.00 msec
root dispersion is 14.62 msec, peer dispersion is 3.26 msec
loopfilter state is 'CTRL' (Normal Controlled Loop), drift is 0.000000000 s/s
system poll interval is 64, never updated.
NTP-relevant config is as follows (no ACLs, outbound UDP 123 allowed on perimeter firewall):
clock timezone UTC 8 0
ntp server 3.sg.pool.ntp.org
I have configured a pair of stacks in Hong Kong for NTP (though that was a couple of months ago and I recall that those were a pain at the time as well) and those are working fine.

Much to my annoyance, the switch stack is now synchronised. No configuration changes were made in the interim; it just looks like it needed a long time (well over an hour in this case) to start syncing properly.

Serial numbers on 3750 stacks

CW Contracts reporting reports the master SN. How can I pull all the SN for all devices in a 3750 stack for asset/inventory purposes?

kathegaj2 wrote:First, thanks to everyone that answered me, it feels effective when you get some kind of answer.So, nothing in reports that can assist with inventory-ing serial numbers for equipment rather than loopback management.I have built Netshow jobs that run sh ver | inc System serial and sh diag | inc PCB and in a large environment these are sloppy to parse.I checked also Contract Status and these also just apply to the master serial. Any other ideas?
You need to create a Custom Report Template in RME Reports.
- Association : don't pick anything
- Inventory Group : Chassis
- Attribute : Chassis Serial Number
- Operator : Contains
- Value : All
Click "Add", then "Save Changes", then Finish.
Then you use your custom report on a selection of device (using Report Generator, Inventory, pick your custom template), and you should be good to go. I then export it to CSV for further editing, sorting, etc.
HTH.
Alex.

Etherchannel issue between 3750 stack and WS-CBS3012 for IBM blade centre

Hi,
We are trying to configure Etherchannel between four ports of cisco 3750 stack(2ports from one switch of stack and two ports from another switch of same stack). We are facing issues with this setup. The ports in WS-CBS3012 are going to err disable mode.
Is there any limitations associated with such a cross-stack etherchannel configuration. Please suggest if there is any particular sequence of configuration involved.
Switch1 in stack
int gi 3/0/3
switchport mo trunk
switchport trunk allowed vlan 10-30
sw tr en dot1q
channel-group 1 mode on
spanning-tree guard root
switch 2 in stack
int gi 3/0/3
switchport mode trunk
switchport trunk allowed vlan 10-30
sw tr en dot1q
channel-group 1 mode on
spanning-tree guard root
int port-channel 1
switchport mode trunk
switchport trunk allowed vlan 10-30
sw tr en dot1q
channel-group 1 mode on
spanning-tree guard root
in WS-CBS3012 ports are configured with trunk,allowed vlan and etherchannel configuration with mode on.
With Regards,
Madhan kumar G

Hi,
The commnad "no spanning-tree etherchannel guard misconfig" on WS-CBS3012 resolved the issue.
Regards,
Madhan kumar G

VLAN on 3750 Stack

I am in the process of getting a 3750 switch stack installed. The stack will use layer 3 and will replace a 5505 layer 2 switch. The 5505 has all ethernet ports set to vlan 110.
My 3750 stack will also have all fasethernet ports in vlan 110.
I wanted to do as much of the up front installation prior to cutover, but did not to cause any problems in my vtp domain, so for the moment I have shutdown vlan 110 on the 3750 stack
I noticed that as soon as I did it took the following off of every fastethernet interface in the stack:
switchport access vlan 110
switchport mode access
While I sort of understand why..it has caused a little trouble because I have recently added another 3750 to the stack and was planning on configuring the rest of my interfaces using port range.
I assume the commands will be added back as soon as the interface vlan 110 is taken out of shutdown.
I was just taken by surprise that it modified the configuration as such and has made it hard to configure the other fasethernet ports I have added.
Hope this clear. Can anyone explain this a little more for me. Thanks

I want to try and add some clarification
I have 2 3750-48POE's in a stack...so I had 96 ports
each fastethernet interface on both 48 port switches was configured like this:
interface FastEthernet1/0/1
switchport access vlan 110
switchport mode access
switchport access vlan 410
switchport port-security
switchport port-security aging time 2
switchport port-security violation restrict
switchport port-security aging type inactivity
priority-queue out
mls qos trust cos
no mdix auto
spanning-tree portfast
spanning-tree bpdufilter enable
spanning-tree bpduguard enable
after shutting down the vlan 110 interface..Here's the config currently:
JDC-3750S-12#sh run int vlan110
Building configuration...
Current configuration : 199 bytes
interface Vlan110
description 10th, 11th, 12th Fl - Data
ip address 10.4.110.1 255.255.255.0
ip helper-address 10.4.1.100
ip helper-address 10.25.192.7
ip pim sparse-dense-mode
shutdown
After shutting down the interface for vlan 110, each fastethernet interface became
JDC-3750S-12#sh run int fa1/0/1
Building configuration...
Current configuration : 388 bytes
interface FastEthernet1/0/1
switchport access vlan 410
switchport mode access
switchport port-security
switchport port-security aging time 2
switchport port-security violation restrict
switchport port-security aging type inactivity
priority-queue out
mls qos trust cos
no mdix auto
spanning-tree portfast
spanning-tree bpdufilter enable
spanning-tree bpduguard enable
1.So you see that switchpot commands for vlan 110 got removed.
2. I have added another 3750-24 POE switch since doing this and wanted to use port range to make my additional set of ports like the ones in the original config.
I can't do that now because the vlan 110 info on the interfaces is gone.
I'm just trying to understand what this thing is doing to me. Hope this helps

Uplinks on 3750 Stacks

We are at the early stages in deploying a Campus LAN, at the access layer we are planning on using 3750 stacks with 2 x 2gb etherchannel uplinks going to diverse core switches; what is the best practice for the cross-stack etherchannel port assignment. E.g. Would it be best to put the first etherchannel uplink on the stack master and the second etherchannel on a non-master switch? Also what are the recommendations for using STP (R. PVST+) or load balancing in this scenario?

For cross-stack EtherChannel configurations, ensure that all ports targeted for the EtherChannel are either configured for LACP or are
manually configured to be in the channel group using the channel-group channel-group-number mode on interface configuration command. The PAgP protocol is not supported on cross- stack EtherChannels.
Here is the procedure from the 3750 12.2.25 docs.
This example shows how to configure a cross-stack EtherChannel. It
assigns two ports on stack member 2 and one port on stack member 3 to
channel 7 using LACP active mode:
Switch# configure terminal
Switch(config)# interface range gigabitethernet2/0/4 -5
Switch(config-if-range)# no ip address
Switch(config-if-range)# no switchport
Switch(config-if-range)# channel-group 7 mode active
Switch(config-if-range)# exit
Switch(config)# interface gigabitethernet3/0/3
Switch(config-if)# no ip address
Switch(config-if)# no switchport
Switch(config-if)# channel-group 7 mode active
Switch(config-if)# exit
check out the following link for more information on configuring Etherchannels :
http://www.cisco.com/en/US/customer/products/hw/switches/ps5023/products_configuration_guide_chapter09186a00801a658f.html#12539

Sg-300 - 3750 stack with SPANNING-TREE root problem.

Morning. I think ive configured a few hundred switches, maybe a thousand in my time, but never have a faced such horribleness that is the SG-300. After this week, I think ill refuse to touch them.
Got 2 voice vlans and running a few vrf's on a 3750 stack. but this discussion is about layer 2.
2 x 3750 stacked
1 x voice switch sg-300 company A voice vlan 18 - Po1 up to 3750 distributed etherchannel Po1 (LACP active both sides) 2 ports in channel
1 x voice switch sg-300 company B voice vlan 19 - Po1 up to 3750 distributed etherchannel Po2 (LACP active both sides) 2 ports in channel
Allowed vlans on both sides (command on Port-channel) are data A, Voice A, Mgt A to switch A
Allowed vlans on both sides (command on Port-channel) are data B, Voice B, Mgt B to switch B
It seems that these switches are limited to one voice vlan....
and that spanning tree BPDU's are ignored (or not recevied- havnt released the shark yet). let me explain.
originally when using "smart port" the switch with the lowest mac address, whatever Voice vlan was configured would take over the other switche's voice vlan, argh what a nightmare.
I gave up on the GUI as its far to complcated and have Almost got this working.
I am now using auto voice vlan, but have disabled smart macro. I hope that disabling smart macro stop other switches from learning the switch with the lowest mac address's voice vlan. So far so good - in the LAB. No where was it documented in the cli guide how do disable this stupid feature.
DHCP is working from scope on core, can mange the switches etc etc, access vlan voice vlan all good (after a monster battle).
Now I have an issue with spanning tree.
spanning tree priority for vlans 1-4094 on the 3750 is 4096.
spanning tree priority for vlans 1-4094 on the SG-300's is 6xxxx.
ALL switches think that they are the root. (well the "logical" 3 of them) The 3750's for all vlans, and the SG-300 for the one instance as it doesnt support per vlan. (I am not interested in trying MST here..this is not a datacentre)
On the 3750's Ive tried ieee, pvst, rpvst, while matching the non per-vlan equivalent on the SG series.
What is the difference between a General port and Trunk Port on a SG-300 specific to spanning tree, native vlans (when you can just configure an untagged vlan anyway!!) and what is the relevance to the way the bpdu's are carried?
And why the need for a PVID, when you can tell a port what is tagged and what isnt.
Does the trunk need Vlan1 to be explicitly allowed, and untagged? Does the Po trunk need to be a general port with PVID configured? in vlan 1?
I need to sort this, as cannot put an access switch into production that thinks it is the root of the tree. I wish I had a 2960.... a 3500XL..anything
Does anyone have CLI commands that can help here?

F.Y.I for catylyst heroes - here is the equivalent config for SG-300 - Vlan1 is required on the allowed list on the catylyst side (3xxx/4xxx/6xxx)
In this example:
VLANS - Voice on 188, data on 57, management on 56.
conf t
hostname XXX-VOICE-SWXX
no passwords complexity enable
username xxxx priv 15 password XXXXX
enable password xxxxxx
ip ssh server
ip telnet server
crypto key generate rsa
macro auto disabled
voice vlan state auto-enabled !(otherwise one switch controls your voice vlan….)
vlan 56,57,188
voice vlan id 188
int vlan 56
ip address 10.230.56.12 255.255.255.0
int vlan1
no ip add dhcp
ip default-gateway 10.230.56.1
interface range GE1 - 2
switchport mode trunk
channel-group 1 mode auto
int range fa1 - 24
switchport mode trunk
switchport trunk allowed vlan add 188
switchport trunk native vlan 57
qos advanced
qos advanced ports-trusted
exit
int Po1
switchport trunk allowed vlan add 56,57,188
switchport trunk native vlan 1
do sh interfaces switchport po1
!CATYLYST SIDE
!Must Explicitly allow VLan1, this is not normal for catalysts - or spanning tree will not work ! Even though it’s the native vlan on both sides.
interface Port-channel1
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,56,57,189
switchport mode trunk

Question about 3750 stack

Hi,
I have 3 3750 switches: WS-C3750G-12S-S, WS-C3750G-16TD, WS-C3750G-16TD.
They are connected via Stack Cable in half-duplex mode.
I have a 10GE module(X2-10GB-LR=) on WS-C3750G-16TD.
the bandwidth of the logical switch should be 32Gbps. My question is about oversubscribe. totally there are 44 Giga ports. how these 44 Giga ports and 1 10Giga port share this 32Gbps? And what's mean half-duplex for stack mode?
Thank you very much.
Regards,
Sha

Hello Sha,
this might not directly answer your question, but the way I understand the StackWise technology is that the switches in the stack form a logical ring, with a maximum backplane throughput of 32Gbps, as you already said. Each packet on each switch is load-balanced across the ring. The ring/backplane supports 32Gbps max, if you have more ingress bandwidth than that, the 32Gbps will still be the limit.
I found this article, which explains some of the issues, you might want to have a look at it:
Cisco Catalyst 3750 stackable switches
http://www.networkworld.com/reviews/2003/0811revcisco.html
HTH,
GP

Etherchannel two cisco 3750 stacks for iscsi?

I have two sites connected by 96 strands of fibre. At each site I have an IBMv7000 relicating to the other one. For iSCSI traffic I have two Cisco 3750 switches, each are in 2 switch stack.
SAN A                         Fibre Link                          SAN B
        |                                                                        |
Cisco Stack A =========================Cisco Stack B
        |                                                                        |
        |                                                                        |
iSCSI Clients                                                       iSCSI Clients
My question: Is it ok to connect the the two stacks with etherchannel using the fibre links? Will is provide the necessary redundancy, if one of the interfaces goes down?

What model numbers of 3750 are you using?
What is the distance between the stacks as this will dictate your fiber run modules.

Connecting 3750 stacks

Hi,
I have an existing stack of 9 x 3750 switches (stack1). Due to a proposed data centre move I will need to create a new stack in the new DC (Stack2) and slowly migrate all the switches over to it. Both stacks will need to be fully active during the migration process.
I have emptied 5 of the existing 3750's and removed them from Stack 1 in preparation. I know I can connect the two stacks using etherchannel, but that is about it. I've been searching for any documentation, or best practices but can't find anything relevant to my scenario.
I have multiple VLANs so my questions are -
What is the best method of connecting the two stacks initially?
Stack 1 has an IP address for each VLAN that is the default gateway, so how would I IP the second stack VLANs?
I believe the VLAN Db on Stack1 will be shared when I connect the stacks, what will happen when I retire stack1?
Any help or relevant links greatly appreciated. I've posted this in the getting started forum as although I have done very basic Cisco admin this is a step up for me, if the mods think it should be moved elsewhere please do so.
Dave

What is the best method of connecting the two stacks initially?
If resources allow, etherchannel is a no-brainer.
Stack 1 has an IP address for each VLAN that is the default gateway, so how would I IP the second stack VLANs? HSRP with the default gateway for each VLAN as the Virtual IP Address.I believe the VLAN Db on Stack1 will be shared when I connect the stacks, what will happen when I retire stack1?
Depends if VTP mode, password and domain is configured correctly.

3750 stacking questions (2)

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