Cisco Switching/Routing :: Two 3750 L3 Switches Connected Via Trunk
Jan 29, 2012
I have client who has two distant offices with 3750 L3 as core (do all vlan routing for local office) and multiple L2 access switches with multiple VLAN’s connected to it. First 3750 is hub also connected to internet, second 3750 is spoke and acting as a router on stick. We have eigrp configured on both side ISP provided client 100Mbps link as a trunk with two vlan; vlan10 for voice and vlan20 for data. We assigned two small subnets to these vlans 10.15.17.0/29 and 10.15.17.9/29. Hub addresses are 10.15.17.1 and 10.15.17.9 respectively. How to force voice over VLAN10 and data via vlan20, but still do some load balancing? How to setup default route on second (router on stick) switch?
I have a 3750 as a core and have a series of HP Procurve switches that are daisy chained using one port. I have two vlans on the port now (6 &9) and everything works fine, all switches communicate and end devices on the switches are also talking. There is a requirement to add a device towards the end of the chain which requires it to connect using Vlan1. Once I add Vlan1 to the port onthe 3750 I lose connectivity to all the HP switches.
I have 2 PE routers connected to each other via 2960S and 3750 (non-metro) switches:
[PE1] -- [2960S] --  -- [2960S] -- [PE2]
I will be sending voice and data traffic between the two and my voice traffic will be marked DSCP EF & EXP 5.
Since the 2960's and 3750's can't match on the EXP bits, I am wondering if the "mls qos trust dscp" command still works. Is the 2960/3750 able to match on DSCP even though there's an MPLS header on top of the IP packet?
I'd like to avoid having to tag my VLAN traffic on the PE and rely on COS to achieve QoS in this case.
A specific switch port which happens to be part of a 2 switch 3750 Switch Stack is seeing multiple CDP packets from 3 extra switch port interfaces that are not directly connected. Noteworthy is that the far end devices have the correct CDP entries and I physically confirmed at least two of those connections that lead to the switch "upstream to the culprit switch". Tricky part is that its production so room for maneuvering is limited. At some point I disabled all Ports save for the real uplink and the problem momentarily disappeared. Re-enable the interfaces problem resurfaces. Is there an explanation, technique to eliminate the culprit with minimal disruption?
I am troubleshooting a fiber connectivity issue.Now I have two switches, one is 3750, and another is small biz 300 series switch. Both switch has a single mode smf gbic. Now I have two swtiches face to face and connect with a single mode cable. Do you think if I would get a link light on? Both ports are no shutdown.
Cisco 4506-E port configuration WESTERN-4506-01#show int g4/47 GigabitEthernet4/47 is down, line protocol is down (notconnect) Hardware is Gigabit Ethernet Port, address is 0022.554c.01fe ( fe) Description: Trunk to 425
I have a couple 3750 switches that I am trying to run VTP Version 3 on.one as primary and the other as "server" which implies secondary from my research. [code]Additionally, running a show VTP devices yields a "No VTP3 devices found" on both devices. Despite ensuring that the domainname and password match.I have a patch cable from Gi1/0/1 on switch one runnning to Gi1/0/1 which from what I read is acceptable on GigE.
Currently we have a 6513 core (running IOS and doing limited routing) with VLAN Trunking to about a dozen 3560 edge switches, with various VLANs going to each of the edge switches. All works well. We are downsizing and replacing the 6513 core with a 3750G stack. We have the stack up and running in the lab, and want to slowly (as we move floors) migrate all of the edge switching to the 3750 stack.
The plan is to connect the 3750 stack to the 6513, then slowly migrate the edge switches to the stack (from the 6513). I would like to put in place 4 x 1GB trunk links between the 6513 and the 3750 stack before I start moving edge switches to ensure adequate bandwidth. Once all of the edge switches are on the new 3750 stack, I will start to decommission the 6513.
What is the best way to configure the links between the cores (old 6513 and new 3750 stack)? I can easily get the edge switches configured to the 3750, but am worried about the core links. I really want to avoid having to perform an all-at-once cutover of the cores. Another question is when do I try and migrate the VTP server role from the 6513 to the 3750 stack? I could simply make everything transparent, and ditch server-based VTP, as we rarely change or creat VLANs.
Is it possible to rate limit on a L2 trunk port on a 3750?
current port config and ios are as follows;
interface GigabitEthernet1/0/50 description *** Connection to Fiber Link *** switchport trunk encapsulation dot1q switchport trunk allowed vlan 1,172 switchport mode trunk end flash:c3750-advipservicesk9-mz.122-46.SE.bin
i was wondering if the "srr-queue bandwidth limit 10" command would work to limit the output from this interface to be 10 % of the port bandwidth and then the same command could be done on the other side.
I am taking only undersize errors on catalyst 3750 trunk interface (attached some outputs)...the other end is a 4500 switch and the interface is clean..can this be related to any bug ? this is my root port and often leading to trouble sometimes STP BPDUs transportation are affected..
We had a core switch (Cisco 4503), distribution switches(Cisco 3750) and access switches in our network and consists of many vlans. Almost all vlans uses DHCP Pools. But for few vlans DHCP is not yet configured due to initial design poblems. Recently one of the rogue user in vlan 1 connected to one of the access switch send rogue arp packets to the network (suspecting arp packet with interface vlan 1 ip of core switch with wrong mac-address (gateway ip of vlan 1)) and resulted in a prolonged network outage for the vlan 1. Any way we are going to seggregate vlan 1 into different vlans, but before that we need a temporary plan to block such kinds of attack like enabling DAI in the switch. I have checked the DAI implemenation feasibility with my knowledge and found that it is not possible to configure to the access switches(Cisco 2960) in which the user directly connected. But found that Distribution switch connected to that particular access switch seems to be able to configure since DAI commands are available to configure in switch.
Is it possible to block ARP packets with the interface vlan 1 IP Address with rogue mac-address by configuring DAI in the above mentioned Distribution switch and the port connected to the mentioned access switch?
I've been having a debate with a colleague about QOS COS values. My colleague says I need to use COS values across layer 2 trunk links between access layer switches and core switches. My argument is if phones are marking packets with DSCP values I don't need to be concerned with Cos.The reason I ask is we're implementing a new phone system, the ip phones will mark RTP traffic wih dscp value EF and Call signaling with DSCP value of CS3. If my understanding is correct I can trust the dscp values of the phones. We are using Cisco 4507 switches which I believe automatically trust dscp values so I would just need a class-map to match the dscp values and apply the output policy map on the egress interfaces as follows? [code]
We have 7 3560's in 7 different locations connected to our providor for wan access. Our provider has given us a copper cable at each point and we have connected it directly to our 3560 switch at each location. Each port is configured the same way at each location. Each switch is running eigrp.All of the switch ports on each switch are configured as a trunk and vlan 299 had the ip address for the eigrp connection: [code] This setup is working as each switch see's all of the other switches as an eigrp neighbor. We have also made sure that the switch at our head office has spanning tree priority for vlan 299.
So the problem is, if there is a change in the topology at one of the locations it usually causes one or more of the other connections to go down for some reason. We just cannot pinpoint what is causing this change. There are no log's or anything other than an eigrp hold time expired message.?
Is it possible to use Port Security mechanism between two switch (3750 or 3560) ports while trunk has been configured? If it's not possible, is there any other way to ensure that no other Switch can be connected other then the one switch which has been configured/placed by a network engineer?
I faced with a strange behavior of ME3600.For testing purposes I linked Cat3550 and ME3600 switches via trunk mode. All interfaces are in Up state. But I couldn't ping SVI200 of Cat switch from ME3600 and vice versa. [cde]
This scheme perfectly works with another L3 swithes. For example Catalist3750. I know that ME doesn't support VTP, DTP and so on. Also, I've tried latest software.
I am looking into the possibility of using private vlan's for some dmz implementations however I do have what may be some very rudimentary questions. It seems straightforward how to configure the primary/secondary vlan configuration as well as associating them. However in my case I would be looking to configure the PVLAN on a 6500-vss platform acting as the router while all of the hosts which I would desire to have in the isolated vlan would be spread out across a number of older Cisco switches which only support "protected port" setup or Procurve switches all of which I do not have budget to replace with something newer. So in my scenario I would have a 6500 connected by trunk to multiple switches which only support a protected port setup such as a Procurve (top of rack) or a Cisco 2950. As the Procurve or 2950 would not support Private VLAN setup, do I then just configure the secondary vlan to be allowed across the trunk from the 6500, configure that vlan on the Procurve or 2950 (as vtp will not foward the info for the secondary vlan) and assign that vlan to the host port as well as setting it as a protected port and this will communicate just fine across the trunk to the router as well as stopping the protected port in top of rack switch 1 from being able to communicate to a protected port in top of rack 2,3,etc? If the above scenario is what needs to be done, do I just use a regular trunk or do I have to use a PVLAN trunk?
we recently aquired a managed services job and have to do a overhaul of the vlan configs and have a whole dozen WC2948G's trunk between a set of ports as well as trunk out a LAG channel setup to non cisco equipment. the deal is the lacp-channel works properly on both ends but no routing of vlans between ports and between the lag trunk are working.
theres alot of settings in the config and im planning on clearing it and starting from scratch but before i do i want to know where my problem lies.
If I have two stackable switches one switch uplinks to one 6509 core switch and the other connection uplinks to another 6509 core switch, and also the other stackable switch does not connect to the core switches. Because I am using hsrp and also we are not using vss then one uplink to the core is not in used only ones is so then how does creating an etherchannel between does two uplinks to both core switches benefit me in anyway such as more bandwith and using both uplinks at the same time or I'm I wrong?
If I have two stackable switches were only one stackable switch has two uplinks one uplink goes to one core 6509 switch and the other uplink goes to the other 6509 core switch can a Layer 3 etherchannel be used if each uplink go to a different core switch, by the way hsrp is running between both switches and also can you give an example how data will be routed from the stackable switch through the ethernetchannel to one of the core switch accross the WAN to another core switch?
Is there really any reason why you wouldn't use spanning-tree portfast on a trunk port other than a trunk between two switches? We have it enabled on all ports except for the fiber trunk between two non-stacked switches and the trunk ports connected to our Astaro firewall.I'd like to enable it on the ports to the firewall unless that would cause issues.
In my customer having 3750 switch and they have simply assign IP address for vlan and enable telnet in switch and other things are same as default switch.In this switch they have connected 8 cisco layer 2 switches(6 managed and 2 unmanged switch) and approximately 5 servers connected in this switch.In a particular interval,users accessing File server are connected to 3750 switch become hanged for few min.This happen for some particular interval.users accessing this server becomes entirely hanged for few min,then i have configured port monitor cmd and i have installed one wildshark tool to host connected directly to that switch.
I am using a 3750 as a default gateway for multiple Vlans on a few 2960 switches. The trunk lines are configured and working and I have assigned ip addresses to each of the Vlan interfaces on the 3750. My issue is that I can only ping the ip address on the Vlan interface of the 3750 if I have a working computer plugged directly into the Vlan on the 3750. I only have 3 vlans on the 3750 that have hosts directly connected (vlans 2, 10 and 40) the other vlans ( 20 and 70) don't have any clients plugged into them on the 3750 but the hosts reside on 2 different 2960s that connect via trunk ports. How do I keep the vlan interface on the 3750 switch pingable when I don't have hosts directly connected in that vlan on the 3750? (yes, I have enabled ip routing on the 3750)
I have a simple design with 3750. I configured a route-map which define a next hop. I defined this route-map on a policy on a vlan interface.When I test some ping and a debug ip policy and it seems that my policy never match.Is there any mechanism that prevent the switch from using PBR? I think of CEF .
I have a simple design with 3750.I configured a route-map which define a next hop.I defined this route-map on a policy on a vlan interface.When I test some ping and a debug ip policy and it seems that my policy never match.Is there any mechanism that prevent the switch from using PBR?
Any method of forcing a non connected switch port LED to blink for a certain number of times regardless if there is anything connected.The purpose of this is we have remote 3750 switch stacks and quite often have to tell non technical staff to patch to a certain port. It would be much easier if we could say "Connect it to the empty port which just started blinking orange" as the port numbers are difficult for them to see in these locations.A similar feature is available in the ethtool package for linux which makes it really easy for identifying ports on servers. It would be great if a similar feature is available on Cisco switches.
One of the ports on the 3750 stack was configured for VLAN121. It was changed to VLAN40 and the configuration saved. Both VLANs exist in the switch configuration. As soon as a host was connected (in this case, a label printer) the port VLAN reverted back to VLAN121.
Switch A connects to Swich B and C using port channel. I am going to bring down one link on each.
switch A is server farm , switch B and C are core 01 and 02 . and all are 3750 switches.
1. what will be the impact on the network in terms of spanning tree recalculation 2. what duration are we talking about until the spanning tree convergence happens? 3.I plan to shut down the link from CLI to bring down the links
I have a small campus network using 3750 stackable switches and a 3725 router (see diagram below). Currently the 3725 router is handling inter-vlan routing for the campus and it looks like it's not able to handle the amount of traffic we're pushing. The router CPU sometimes hits above 90% due traffic load. What I would like to accomplish is move L3 process over to the 3750 MDF stack and the IDF1 stack. I am thinking creating SVI's on both MDF stack and IDF1 stack, run HSRP between the two stacks and may be do load balance traffic between the two stack as well.
Looking for feedback from other organizations that have large 3750 stacks. I've got one stack of (8) 3750's composed of (6) 3750G's and (2) plain 3750's. This particular stack is usually unresponsive to SNMP queries and often fails to write config when we make changes. After a couple tries it will finally go. Part of my probably here is likely the plain 3750's that always boot faster and come up as the master. I should manually set the master to one of the G's. What I'm wondering is who else has 7-9 3750's stacked and are they performing well for SNMP, telnet, etc? I've got another newer stack of 7 3750E's that I need to add one more switch to. Need to decide if I want extended downtime to break the stack up or just add the 3750X to make member 8 and hope it performs well. I have 50+ 3750 stacks working great on our campus.