Cisco Switching/Routing :: 3750X - Valid Frames / Too Large
Aug 20, 2012
We have a brand new 2 x 3750-X stack running 15.0(1)SE3 with C3KX-NM-10Gs installed in each switch. An HP C-Class server enclosure with Virtual Connect Flex-10 modules is connected to each of the 10G ports using twin ax cables and they seem to behave OK apart from some random packet drop which appears to be within the enclosure and not without.
However, when we were investigating this, we found a little oddity ... even though we have jumbo frame support enabled on the 3750-Xs, we are getting a significant "Valid frames, too large" received count on the interface, and a "Too large" transmitted count. I've looked around and can't find a definitive reason for this count to go up - it doesn't seem to be a jumbo frames thing, more an unexpected-additional-field-in-a-header type thing, like when you have a V LAN tag in a DTP frame. Any thoughts as to why I might be getting these from a new server enclosure?
SW-STACK-CORE-3750X#sho int t2/1/1 controller
TenGigabitEthernet2/1/1 is up, line protocol is up (connected) Hardware is Ten Gigabit Ethernet, address is a44c.116e.55b5 (bia a44c.116e.55b5) [ code]....
I've to enable it on 3750 and nexus 7K switches. what are the steps involved? can we enable jumbo frame per port instead of enabling globally? i.e. we will only have few ports that will be using jumbo frames, rest of the ports will be using default 1500 MTU size.
We have a requirement to send span traffic to a destination port for monitoring purposes on two 5000s with some 2000 fex boxes attached. Some of the servers are making use of frames larger than 1500. we have not changed any mtu configuration on the 5000 since installation, and I can see the policy maps is still on 1500.
My first assumption would be that frames larger than 1500 will not be dropped, but it seemingly not (see below). is there a reason why the switch would forward jumbo frames? Also, is there a limitation on MTU for span traffic? There is a MTU command under the span session, but the maximum is 1518. From what I can read the frame will be truncated if it exceeds this. Does that mean the fragments will be dropped?
I believe i've enable jumbo frames on our Nexus 7010, one in each data-centre.
system jumbomtu 9216. Also on the interfaces mtu 9216. And can see MTU 9216 bytes, BW 20000000 Kbit, DLY 10 usec on the port-channel between them. Though when i ping between vlans at each site with large packets i get 30% drops and if i set the DF bit in IP header to yes - 100% loss.
8798 bytes from 10.200.12.2: icmp_seq=19 ttl=254 time=8.024 ms --- 10.200.12.2 ping statistics ---20 packets transmitted, 14 packets received, 30.00% packet loss
I understand that jumbo frames need to be enabled end-to-end. I have two ESX hosts connected at each site. I want to enable jumbo frames for those ports, but what if not all host on the ESX are using jumbo frames, will I have drops and connection failures? So if i have two sites, each with a 6509 connected via a trunk and need to enable jumbo frames for a vlan between the sites how do I accomplish this?If I enable jumbo frames on the trunk link how does that impact other traffic between the sites?
I have a Cisco Nexus 3064 that I am using as part of a flat network for the Lab. I have 30 Virtualization Servers(MS HyperV and VMware vSphere) connected to this switch and I want to enable jumbo frames. The Virtualization Servers are able to ping the local VM's using 8K bytes. However I am unable to ping from server to server using 8K bytes. I have configuration (in abbreviation). All the servers are in the same network which I configured as L2 ports with the "switchport" command. However, the interface "MTU" command is unavailable in L2 mode. I am only able to get the interface "MTU" command only in L3 mode with the "no switchport" command on the interface.
# int eth1/2-45 # no switchport # mtu 9216 # no shut
I can ping the servers with less than 1500 bytes, but anything larger fails.
I have a Cisco Catalyst 3100 blade in a Dell server chassis that is trunked to a 6509.
When doing a protocol capture, I see large frames being sent from one of the servers in the chassis.
Example:
TCP:[Continuation to #1701] [Bad CheckSum]Flags=...AP..., SrcPort=HTTP(80), DstPort=2667, PayloadLen=2831, Seq=1489611217 - 1489614048, Ack=1719592331, Win=65535 I see lengths up to 6900+ bites coming from the server.
The switch has the global MTU set to 1500
system mtu routing 1500
and I can't seem to set this at the interface level. The server is configured to send 1500 length frames. Why am I seeing these jumbos? (the server is Windows 2003)
I have a pair of Catalyst 3560 GB switches that are trunked with two of the standard ports, and that have trunk ports connecting to a failover pair of PIX 515e's. We're considering adding a pair of cluster database nodes and an iSCSI SAN, both of which would need a dedicated interconnect VLAN that I'd like to employ Jumbo frames on. I don't necessarily need the VLANs to traverse the firewall trunks since they're private interconnects, but I need each host to traverse the switch trunks.
Since it seems I can only enable Jumbo frames on the entire switch (current standard frame size is 1500 and jumbo is also 1500), when I enable it what kind of possible negative impact could this have on my trunked ports as well as my host connections? I've read mixed reviews of users with iSCSI SAN devices seeing terrible performance when enabling jumbo frames so I'm apprehensive about enabling them on an existing network.
The server team has asked me to implement jumbo frames on a single VLAN, the one they use for v motion. We have two pairs of 5548s, each pair running VPC for most connections. I am aware of many postings that describe how to enable jumbo frames globally, like this:
policy-map type network-qos jumbo class type network-qos class-default [code].....
I am not clear how I can extend this principle to one VLAN only.
Also, I am aware of a posting [URL], that shows some pitfalls of implementing jumbo frames in a VPC configuration. Pretty well all my connections are VPC, including all the FEXes, which are all dual-homed. In many cases, the VPC extends through to the servers so that the servers run port.channels across two FEXes. I am unclear whether the pitfalls are still valid, or whether I have to wait until my next maintenance slot (6 months away) to implement jumbo frames. Can jumbo frames be implement safely on the fly? How does enabling jumbo frames fit in with "conf sync" mode?
We have a number of sites which have high-speed L2 links which terminate on our L3 switches at each site. The ports are between the sites are placed in routed mode.
I would like to use Jumbo frame between two of the network which will communicate across sites and 1500 mtu on the rest, is this something which is possible?
From my understanding is the mtu is set on the interface therefore if I set the mtu on the L2 link ports on both sites to 9000 then would this cause a problem for the 1500?
We are currently using two Nexus 5548UP's as our Datacenter Network Core. I have a pretty simple objective: I would like to enable Jumbo Frames on a single VLAN only(VLAN 65). This VLAN is used strictly for backups. I do not want to enable Jumbo Frames on the other VLANs(VLANs 1-10). Im not sure what the best way to do this is.....or if it is even possible but I am hoping to get some configuration examples.
I have a problem with x4648-rj45V+E module, which is not forwarding frames/packets in my 4507E switch. I have done the diagnostic and the module test is passed. When i try to ping from one PC to another in the flat network, icmp is not forwarding. Even i cannot see the mac addresses in the mac address-table. But i can ping to my management port in the sup module?
I attempted to enable jumbo frames on a Nexus 5010 (NX-OS version 4.2(1)N1(1)). I created the policy map below and lost access to the switch.
policy-map type network-qos jumbo class type network-qos class-default mtu 9216
After recovery I see from the logs that all vlans and interface were suspended. I've attempted to look for reasons for a compatibility issue but I am unable to find what is checked and what could have been incompatible. The other troubling thing is the adjacent switch suspended its interfaces too but no change was done there. What I need to look out for so that this does not happen again?
2011 Nov 22 23:43:09 phx-ipcg1dwfcma %ETHPORT-3-IF_ERROR_VLANS_SUSPENDED: VLANs 1,10,601 on Interface port-channel1 are being suspen ded. (Reason: QoSMgr Network QoS configuration incompatible) 2011 Nov 22 23:43:09 phx-ipcg1dwfcma %ETHPORT-5-IF_TRUNK_DOWN: Interface port-channel1, vlan 1,10,601 down 2011 Nov 22 23:43:09 phx-ipcg1dwfcma %ETHPORT-3-IF_ERROR_VLANS_SUSPENDED: VLANs 10 on Interface port-channel508 are being suspended.
I currently have 4 3560 switches connected in a Mesh topology. These are all set to use Jumbo Frames and so are all the Servers that are connected to these.I now need to connect a 2950 switch to 2 of the 3560's which will have only desktop computers connected to it but i do not want to configure Jumbo Frames on this and any of the desktops.
I have an 1841 and started to run into an issue which can be resolved but looking to see what you guys prefer to do in this situation. We allow users to connect the laptop via ethernet and wireless to our network at the same time as well as an iPad or any other wireless technology. With that said, for the most part each user has two IP's at any given point. The issue comes in is that I have a large amount of IP exclusions for servers, printers, switches, etc on the exclude list. I am starting to see that the 255 address are not enough to make a long story short. I am also using the 1841 to handle another range for the voice network, which has no isues. What is the best way to fix this issue? Can I run a virtual VLAN off that 1841 for everyone to use and then have the servers, switches, printers, etc on another one? I want to assume no, as both interfaces are used on the back of the 1841 for the two VLANS running now. Or is the only way to handle this with this device to say that as a policy you can only connect assigned company hardware to the network?
We are migrating from Catalyst 6509 IOS platforms to Nexus 7009. There's the normal differences in commands which is well doucumented. We do have some quite large files containing ACLs varying from 10's of lines to several 1000's of lines. Our normal upload would be done using tftp and then issuing the command 'conf net' on the the 6509. This is no longer the way to do this on NX-OS. I've tried copy ftp: running-config which works fine for small files but for big ones it takes a long time, in some cases I've see it takes 20-30 minutes. The initilal tftp uplaod to the 7009 seems OK but the copy into the running-config is the bit that takes time and initially I thought I'd killed the 7009!! It did finally come back to the prompt. Are the 7009's simply not designed for large ACLs? I did try the configure session (Session Manager) but I couldn't see a way of uploading a file. I tried creating a new session and then exiting it, copying in a file of the same format and then commiting it but it didn't seem to acknowledge the file (checksum?).
A question concerning the use of REP for IE-3000-4TC switches:
In figure 14 of REP pdf URL can you explain why this creates a loop in the system? From the document, I thought REP and RSTP could talk to each other so why does this create a loop if they are exchanging information between each other? Also, if, in figure 14, the two switches in the STP domain that connect to the REP ring, were also connected to each other, would there still be a loop in the system?
Also, what is the recommended max diameter a REP ring should be. I thought I read some place 130 nodes is ok, but I'm looking to confirm this.
Our office lan network is in 192.168.0.0/16 with 300 nodes and 30 server .Since its a large broadcast domain some times it takes large time for copying files.How can we avoid this problem with out changing the subnet.Also how to avoid broadcast storm.we are using cisco 2950 series switch.
we have two 6509E, as our core switches. Recently I noticed that on some connections I have a high output queue drop rate.
These 4 x 2 interfaces (gigabit) are connected to our blade encolure, consisting of 4 x WS-CBS3120X-S. The utilization of the links is really quite low, when I see the increase of the drops. (~=60Mbps). All the links are fiber (SFP) and the distance between the core switches and the enclosure is about 15-20m.
I am not aware of any service degradation on the part of the servers. No CRCs, collisions etc, on the interfaces, apart from the drops.
The line card is a WS-X6748-SFP, but other interfaces don't seem to be experiencing any problems.
I have been searching the message boards and wasn't having much luck. I am running some monitoring sessions on my 6509 and on the VLAN I am monitoring, I am experiencing a really large packet loss. If we hook up a laptop to the destination port and run wireshark we are seeing between 80% and 90% packet loss. I dont see the packet loss on the show port command, but I do on the show int vlan command.
The config is as follows:
Session 2 --------- Type : Local Session Source VLANs : RX Only : 500
[Code].....
I was doing some reading on Egress vs Ingress and I am wondering if the Egress SPAN replication state could be causing the packet loss that we are seeing or does the ingress & learn command override that?
We are receiving a large amount of output drops on 4 interfaces that connect to microwave wireless.This is playing up with our Management system. Saw a bug report but that was for 3750, not the IOS version but was a similar issue. [code] The output errors tend to happen at the same time. All ports are trunks however there are other trunks on the switch that are not having these issues. [code]
I have 2 3560 switches that are running 12.2(25)SEE2. Port security is enabled on some of the ports. Whenever there is a power failure, when power is restored, 1 port on each switch goes to err-disabled. The mac address that causes this is a valid address for that port. Below is the configuration on one of the ports.
Our ISP hands us an ethernet link. ISP router has one address of (for argument sake) 1.1.1.0/30 net, - let's say they have 1.1.1.1 we have the other usable address of 1.1.1.2/30 assigned to our 3825 router. Is it possible to use hsrp or vrrp if there is not two valid/unique "wan" IPs to assign to our routers? For example, if we had a pair of 3825 routers? are we stuck with basically a manual failover or requesting our isp to provide a larger address wan block?
My management has tasked me to give them a high level overview of the different switching we can choose for our new building.
This is what I know so far.4 Closets, each closet has 450 ports,One MDF room that is will contain one UCS Chassis and a Nimble iSCSI SAN.
I am working on the spreadsheet and it looks like this (Not totally filled):
2960s3560x3750x45064510Approx cost (Each, 48PORT, POE+, 10G uplink, Dual PS, IP BASE) 6K7K8K45K75KMax Capacity192432432192384Backplane speed206464520520ProLeast ExpensiveStackable to 9Stackable to 9ProDual PSDual PSDual PSDual PSDual PSProLayer 3 opt Layer 3 optDual SupsDual SupsConExpensiveExpensiveConNo Dual PSConLayer 2 OnlyCannot stack more than 4 For the MDF I would like to use 2 Nexus 5548's with FEX's, and the layer 3 daughter board. For the IDF's I was thinking of two 4010's.
i cant find any difference in these two devices when i am trying to compare throughput.I need upgrade our new POP and there will be around 4900 MAC adresses in VLAN 150 and 130 MAC adresses in vlan 200.Uplink is 1 gig routed internet connection and there is 14 downlinks to separate villages.i found a few differences for eg stack interface on 3750x but i dont need it.
I have a stack of 2 x 3750X switches these are running 12.2(55)SE5. I needed to add some static IP routes and found that the ‘ip routing’ command is not supported. I came across a document that stated “On switches running the LAN base feature, static routing on VLANs is supported only with Cisco IOS Release 12.2(58)SE and later.” So I have upgraded to 12.2(58)SE2, but ‘ip routing’ is still not a valid command.
The release notes state:“On the Cisco Catalyst 3560-X and 3750-X Series, it adds support for 16 static IPv4 routes in the LAN Base image.”
I have read other posts that talk about running the ‘sdm prefer routing’ command which I have done, but I am still unable to add any routes or run the ‘ip routing’ command.
I have an 1811 with several subnets connected to it.I recently installed a 3750x plant and want to bring my interior routing back to it.
All the routing is handled by the 1811 via secondary interfaces on vlan1?
I have 192 ports, and subnets show up on almost all of them. None of the ports are assigned to any specific vlans. Most ports have several subnets on them.
What is the best approach to getting the 3750x to handle the routing?
my company pay a switch 3750 X. WS-C3750X-24T-E. It uses IP services basically but I failed to configure InterVLAN routing. why interVLAN routing doesn't work on my switch?
I am setting up a vm environment for a customer in my lab off site. I have two stacked 3750-x switches, a san, and threes UCS c220 M3S servers for hosts. I am trying to separate the lan traffic, san iscsi traffic, and san management traffic using vlans. The problem is i'm unable to communicate cross vlan with my current config, which I have attached to this post. The only noteworthy things in my conifg is that the ip route 0.0.0.0 0.0.0.0 192.168.83.6 is referring to a switch stack they have on site, that I will connect this stack to using the first two trunk ports on each switch, that I do not have here in the lab. I don't want to cause any confusion in why I have things set a certain way.
Why does my 3750x-12s switch say it's not supported in CNA??? I upgraded to CNA 5.7.1 and still says unsupported. This device is supported or I'm just missing something.I use CNA heavily to manage our MANY vlans.
