2 3750 questions

I have 2 3750's that I have decided NOT to use stackwise. They are replacing 2 3550 switches that were connected via gigastack cable running HSRP. I am going to do the 3750's the same way.
Question 1: I did connect the switches via the stackwise cable to experiment. I have "write erased" both switches but they still seem to think they are connected via stackwise. Ports are numbered incorrectly for standalone. How do I get rid of this?
Question 2: The 2 3750's will uplink via copper crossover. What if anything do I lose not using the gigastack cable?

1)You can use the switch renumber command. For example if all your interfaces have 2/0/x numbering and you want to change to 1/0/x, you can issue the following command
Stack1(config)#switch 2 renumber 1
WARNING: Changing the switch number may result in a
configuration change for that switch.
The interface configuration associated with the old switch
number will remain as a provisioned configuration.
Do you want to continue?[confirm]
Changing Switch Number 1 to Switch Number 2
New Switch Number will be effective after next reboot
2)The stackwise gives you a 32Gigabit backplane ring and offers higher resilience and ease of management. If I were you, I would use Stackwise.

Similar Messages

Port-ACL's on a 3750 - question

I have a 3750 that is connected to another network via a layer-2 type connection. I have a specific set of tcp and udp ports that I want to allow access to via this switch. In taking a look at the documentation I see that I can apply Port ACL's directly to layer-2 interfaces, but that it will only work "inbound" to the switch.
Will this work:
If I have (bad ascii net diagram):
[hosta]--[rtr]--[switcha]-WAN-[switchb]
I want to put an ACL on the l2 uplink from switchB to the wan (WAN is a metro-ethernet type l2 wan extension - rtr is a router) that only allows hosta to hit tcp ports 1000,2000 and 3000 on hosts sitting on switchb. I want to allow hosts on switchb to do whatever they want to hosta. Is it as simple as:
ip access-list 101 permit tcp any any eq 1000
ip access-list 101 permit tcp any any eq 2000
ip access-list 101 permit tcp any any eq 3000
and then applying that ACL onto the l2 uplink interface on switchb? Thinking that since Port ACL's only affect "inbound" direction - allowing inbound connections on the l2 uplink gets the packets onto my hosts on switchb, and there is nothing preventing the return traffic or new tcp connections from hosts on switchb -> hosta...?
Thanks!
-Frank

Yes frank, Your idea seems to be okei.
As per document, You can configure only one type of per-user ACLs on a Catalyst 3750 switch port: router ACLs or port ACLs. Router ACLs apply to Layer 3 interfaces, and port ACLs apply to Layer 2 interfaces. If a port is configured with a port-based ACL, the switch rejects any attempt to configure a router-based ACL on the same port. However, if a port is configured with a router-based ACL and then a port-based ACL, the port-based ACL overwrites the router ACL.
while applying to the interface connecting to l2 port give "in" direction, but anyway out is not supported in l2 interfaces.
so nothing looks preventig the return traffic.

3560 and 3750 - Question about 10/100/1000 ports

I am researching several Cisco products to recommend to a customer. I was wondering if the 10/100/1000 ports at a 3560 switch, will provide gigabit bandwith on each port or if the bandwidth is shared among several ports. The latter is how a 48 port 10/100/1000 line card would behave on a Cisco 4500 when, depending on the card, the gigabit bandwidth will be shared among 4 or 6 ports at a time.
What about 10/100/1000 ports on a 3750?
Thanks

The new Catalyst switches/modules such as the Catalyst 6500/6000, 4500/4000, 3550, and 2950 support 10/100/1000 Mbps negotiated Ethernet interfaces or ports. These ports work on 10Mbps, 100Mbps, or 1000 Mbps speed based on their connection to the other end. These 10/100/1000Mbps ports can be configured for speed and duplex negotiation in the same way as 10/100 Mbps ports on CatOS or Cisco IOS Software-based switches. Therefore, the configurations given in this document for 10/100Mbps port negotiation applies to 10/100/1000Mbps ports as well.
http://www.cisco.com/en/US/tech/tk389/tk214/technologies_tech_note09186a0080094781.shtml

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?

QoS Questions for 3750 Switches

2x3750 switches are stacked and we are trying to simulate traffic congestion at the UTP ports by using Smartbit 6000C. The objective of the test is to see if the QoS setting works in reality even though we see from Wireshark that the packets are marked with DSCP for voice traffic.
Setup is as follows :
Smartbit<->Avaya IP Phone<->3750 switches<->6509 switch.
Please note that the configuration is set on the 3750 switch port as well as trusted on the Cat 6 switch port. However, when I set to continuous traffic with byte size of 64. Even though its a 100Mbps port, the Avaya IP Phone is already acting weird with hanged symptom. Just side note is that performing "show mls qos inter gi2/0/7 statistic" shows that data and voice traffic are marked on the different priority which seemed correct.
1) Is this the right way to test? If not, what should be the correct way?
2) The port that's connected to Smartbit is configured and it seemed that with the continuous traffic, even other IP Phones are hanged even though I have set Smartbit to hit on the IP address of the CAT6 Switch port. This is not normal right as this is supposed to be unicast traffic. Any idea what could be the reason?

Hello Brandon,
I understand your concern and how you want to test, but with the VoIP services you need to understand that there are 2 points (telephones if you want) involved. Your local one, where you might have taken all the necessary steps to protect and prioritize your voice traffic, and the oposite end which also need to have the voice packets prioritized.
Now, from your description, I understand that the packets (voice and data) marked correctly (I believe on C3750), but that's not enough. You need to use CBWFQ together with LLQ to give priority to the Voice traffic over data in case of congestion. Do you have such configuration? Can you show us some excerpt from it?
Next, during the testing, you said that your phone hang-up...where you in a call?
To respond to your questions:
1. The start is ok, but we need more details. You are pushing traffic from Smarbit, this is your local end, but where is the traffic pushed to (remote end), who is receiving the traffic?
2. In theory, you shouldn't have any impact over voice if links are 100Mbit, only if you have such a power packet generator that could fill 100Mbit. What do you mean by "This is not normal right as this is supposed to be unicast traffic"? VoIP is also unicast traffic...
I can see that you are determined to solve this issue, and this is OK as it will help you back with gained knowledge, but I have to warn you that troubleshooting QoS / Voice related problems may be more tricky than you think, as it will involve a strong know-how in these areas.
We will help, but you have to come back with more precise details.
Good luck!
Calin

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

Layer3 Switching and BVI questions 2948l3 to 3750

We currently have a 2948L3 Core switch which does the routing of our two class C ip schemes. I did this using a BVI. We have purchased a 3750L3 gigabit to replace a core switch at another location however it appears some of the bridging that was capable in the 2948L3 is no longer supported in the 3750 or the methods for implementing it has changes.
On the 2948 I configured it like so and everything works great.
ip subnet-zero
bridge irb
interface BVI1
description Kludge for 192.1.11.0/24 and 192.1.12.0/24 to exist within the same broadcast domain
ip address 192.1.12.1 255.255.255.0 secondary
ip address 192.1.11.248 255.255.255.0
no ip directed-broadcast
bridge 1 protocol ieee
bridge 1 route ip
I then add any port into bridge-group 1 and it can route between the two subnets.
The 3750L3 does not support bridge protocol ieee only vlan-bridge. Here is the config of the 3750
version 12.2
switch 1 provision ws-c3750g-24ts
ip subnet-zero
no file verify auto
spanning-tree mode pvst
no spanning-tree optimize bpdu transmission
spanning-tree extend system-id
vlan internal allocation policy ascending
bridge irb
interface GigabitEthernet1/0/1
no mdix auto
interface Vlan1
no ip address
bridge-group 1
interface BVI1
description BVI to allow 192.1.30.0/24 and 10.0.32.0/20 to exist
ip address 10.0.32.2 255.255.240.0 secondary
ip address 192.1.30.1 255.255.255.0
ip classless
ip route 10.0.32.0 255.255.240.0 BVI1
ip route 192.1.30.0 255.255.255.0 BVI1
ip http server
ip http secure-server
control-plane
bridge 1 protocol vlan-bridge
bridge 1 route ip
When i try to add any port to bridge group 1 other than vlan1 it tells me that
% command accepted but obsolete, unreleased or unsupported.
So my question is how would I allow two different subnets to work in the same broadcast domain on a 3750 like i did on the 2948. I've looked all over the cisco site but have not found any info on what config proceeds the bridge ieee command that i used on the 2948.
TIA

Clearly most of the bridging commands are not supported on the 3750.
http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_guide_chapter09186a008017ed8a.html#1018742

Question about configuring Etherchannel on Catlyst 3750

Hi, I have a stack witch catalyst 3750, I mean I have 3 switches ( 1 master, 2 slaves)
My question
Can I configure an etherchannel having 2 interfaces on each switch?
How can I do this?
Thanks
Regards

If you have a stack it should present itself as a single switch just put channel-group 1 desirable nonsilent if you are going to another cisco on each of the interfaces you want in the channel . this is for a layer 2 etherchannel . For a layer 3 etherchannel is somewhat more involved and too long to write here , just go to the cisco.com site and search on configuring etherchannels,3750 .

Question about 3750 mls qos map dscp-output-q and cos-output-q

1. If a egress packet has both Cos and Dscp setting, which map should this packet used to put into queue?
2. The 3750 is doing ip route. After the packet is routed, will the packet keep the DSCP and COS? Or it will just keep the DSCP and using the dscp-cos map to create a new COS.

Apologies for the confusion with the terminalogy.
The question is where you have configured the trust boundaries, do you necessarily trust the DSCP value prior to being routed across your network?
Therefore, although you have explicity trusted the DSCP value, do you still trust the value at the remote peer.
For example, you connect into an MPLS with QoS enabled, you know that the values you are trusting are correct within your network, however at the remote peer/branch they could be remarked by the provider. Therefore do you 'believe' the values, or do you simply not trust them and then reclassify on ingress.
Regards
Allan.
Hope this makes sense..

3750 product question

I have basic product question on cisco 3750 series switches.
I have a few different models here
WS-C3750-24TS-E
WS-C3750G-24PS-E
WS-C3750G-24PS-S
WS-C3750G-24TS-S1U
WS-C3750G-48PS-S
WS-C3750G-48TS-S
WS-C3750X-48PF-S
WS-C3750X-48T-S
Questions
1. What do the TS-E , PS-E, PS-S, PF-S, T-S etc stand for ?
2. Also within the 48 port switches if i have to create a stack , would i be able to mix models in creating a stack ?

show power inline and have taken the details of my second switch ...
Interface Admin Oper       Power   Device              Class Max
Gi2/0/1   auto   off        0.0     n/a                 n/a   15.4
Gi2/0/2   auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/3   auto   off        0.0     n/a                 n/a   15.4
Gi2/0/4   auto   off        0.0     n/a                 n/a   15.4
Gi2/0/5   auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/6   auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/7   auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/8   auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/9   auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/10 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/11 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/12 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/13 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/14 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/15 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/16 auto   off        0.0     n/a                 n/a   15.4
Gi2/0/17 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/18 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/19 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/20 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/21 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/22 auto   off        0.0     n/a                 n/a   15.4
Gi2/0/23 auto   off        0.0     n/a                 n/a   15.4
Gi2/0/24 auto   off        0.0     n/a                 n/a   15.4
Gi2/0/25 auto   on         15.4    Ieee PD             3     15.4
Gi2/0/26 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/27 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/28 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/29 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/30 auto   off        0.0     n/a                 n/a   15.4
Gi2/0/31 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/32 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/33 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/34 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/35 auto   on         10.5    IP Phone 7937       3     15.4
Gi2/0/36 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/37 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/38 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/39 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/40 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/41 auto   on         6.3     IP Phone 7961       2     15.4
Gi2/0/42 auto   off        0.0     n/a                 n/a   15.4
Gi2/0/43 auto   off        0.0     n/a                 n/a   15.4
Gi2/0/44 auto   off        0.0     n/a                 n/a   15.4
Gi2/0/45 auto   off        0.0     n/a                 n/a   15.4
Gi2/0/46 auto   off        0.0     n/a                 n/a   15.4
Gi2/0/47 auto   off        0.0     n/a                 n/a   15.4
Gi2/0/48 auto   off        0.0     n/a                 n/a   15.4

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

Question on ARP table on 3750 switch

Hi,
So I have a cisco 3750 switch directly connected to a 2851 router gig 0/0 interface.
Should the show arp command on the switch show an entry for the IP and mac address of the routers gig 0/0 interface?
I dont see one in there now and was just wondering.
Connectivity between the switch and router work fine right now.
thanks

HI Bill,
if u can ping from Swicth ro router,,,,then please check with this command: sh ip arp.
Just for Info;
To be able to ARP a device, you must have an interface (SVI) on that switch on that network. To ARP a device you must have an interface with a layer 3 IP on the same layer 2 vlan.
You will need to connect to a switch that has an interface on that vlan on it. I would traceroute to the host, and hopefully the next to last hop is the layer 3 switch, or if it's a router, connect to it and do a show cdp neighbors and see if you can find the switch that way. (If you do connect to the router, you'll find the ARP entries there, if it's a layer 3 switch, then it's both a router and switch in one box)
"sh mac address-table". This will give which MAC is connected to which port.
"sh ip device tracking interface gigabitEthernet ". This will give which IP is connectd to a port.
"sh ip arp" will give you a IP to MAC table
Regards
Dont forget to rate helpful posts.

3750 Config Question

I'm running 3750's with 12.2 code. Is there a way to config multipule ports at the same time. Ex I need speed 100 duplex full, on all the ports. How would I config them all at one to thoses setting? Thanks

You can try default interface range
More at this link for 3750.
http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_guide_chapter09186a00801cdea4.html
HTH

Question about 3750 as dhcp server

hi,
With two c3750 switches stacked one customer is plannig to configure those switches to act as dhcp server for about three thousand clients.
Can this configuration affect to the normal behaviour of the stack?
Could come up some problems with this amount of clients?
Thanks in advance

uosambela wrote:hi,With two c3750 switches stacked one customer is plannig to configure those switches to act as dhcp server for about three thousand clients.Can this configuration affect to the normal behaviour of the stack?Could come up some problems with this amount of clients?Thanks in advance
Personally with that many clients i would look to use something like Microsoft Windows DHCP server. Using switches/routers as DHCP servers is fine for a few vlans or clients but for 3000 it is much easier to manage with a dedicated server.
Jon

Metro 3750 DC Question

Can i use only feed A to power 3750DC? Or i have to use feed A and B.
Thanks
Paul

Hi
I did try to find out the same but could find only the voltage ratings which is -36 to -72 VDC.
Had seen 7300 routers with same kinda rating having rating of 3A.
But still would suggest to get the same confirmed with ur vendor.
regds

2 3750 questions

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