ISL trunking and MTU and PMTUD

All,
In the case you setup a ISL trunk from switch to a router (using logical interfaces), does anyone know if the MTU changes on the routers interface and/or the router can cope with the 30 bytes overhead of ISL. I would think that the router can cope with the extra 30 bytes, but i do never see any baby giant frames (1514 + 30 = 1544 bytes frames) in the statistics.
Geert

When a port is enabled for 802.1q trunking the switch will automatically assume that there is an extra four bytes of data appended on, incrementing the frame size of the Layer 2 (L2) packet. Therefore, for implementations that require exactly only one tag to be carried (either 802.1q or Multiprotocol Label Switching (MPLS), but not both), it is possible to force the switchport to accept an extra four bytes of data by configuring it as a trunk port.

Similar Messages

How to configure a port channel with VLAN trunking (and make it work..)

We're trying to configure a port channel group with trunked ports to connect a NetApp HA pair. We want to create two data LIFs and connect them to the switch stack. We are trying to create 2 data lifs, one for cifs and one for nfs that are on different vlans.
We want the same ports to be able to allow multiple vlans to communicate. (trunked)
These data lifs should be able to fail over to different nodes in the HA pair and still be able to communicate on the network.
What this means is that we have to connect 4 ports each for each node in the NetApp HA Pair to the switches and create a port channel of some type that allows for trunked vlans. When we configure the ports, the configuration is as follows (below):
We are only able to configure an IP on one of the vlans.
When we configure an IP from another vlan for the data lif, it does not respond to a ping.
Does anyone have any idea what I'm doing wrong on the Cisco switch?
interface GigabitEthernet4/0/12
description Netapp2-e0a
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10,20,511,519
channel-protocol lacp
channel-group 20 mode active
end
interface GigabitEthernet4/0/13
description Netapp2-e0c
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10,20,511,519
channel-protocol lacp
channel-group 20 mode active
end
interface GigabitEthernet6/0/12
description Netapp2-e0b
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10,20,511,519
channel-protocol lacp
channel-group 20 mode active
end
interface GigabitEthernet6/0/13
description Netapp2-e0d
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10,20,511,519
channel-protocol lacp
channel-group 20 mode active
end
interface Port-channel20
description Netapp2-NFS
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10,20,511,519
spanning-tree portfast
spanning-tree bpduguard enable
end

Our problem was fixed by the storage people. They changed the server end to trunk, and the encapsulation / etherchannel.
I like all the suggestions, and they probably helped out with the configuration getting this to work.
Thanks!
interface Port-channel20
description Netapp2-NFS
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10,20,511,519
switchport mode trunk
interface GigabitEthernet4/0/12
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10,20,511,519
switchport mode trunk
channel-protocol lacp
channel-group 20 mode active
interface GigabitEthernet4/0/13
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10,20,511,519
switchport mode trunk
channel-protocol lacp
channel-group 20 mode active
interface GigabitEthernet6/0/12
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10,20,511,519
switchport mode trunk
channel-protocol lacp
channel-group 20 mode active
interface GigabitEthernet6/0/13
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10,20,511,519
switchport mode trunk
channel-protocol lacp
channel-group 20 mode active

UCS F port trunking and reserved VSAN confusion

We have an existing UCS infrastructre where all the FI's FC ports are connected to the MDS9513 as one to one connection ( no port channel or trunking) and the FI is working as "end host mode" . We are planning to move some crtical production application to the UCS infrastrcture and becuse of that we would like to use the FC port chanelling and F-port trunking. While reading some documents I found that there are some restriction on UCS for VSAN numbering while using the FI for F-port trunking . As per the following doc http://www.cisco.com/en/US/docs/unified_computing/ucs/sw/cli/config/guide/2.0/b_UCSM_CLI_Configuration_Guide_2_0_chapter_010101.html#concept_5223F7F368524A39AB1A47B9F8BFEC8A
it says donot configure VSAN ID range from 3840 to 4079 . The MDS 9513 is running NX-OS 4.2(3) . Our existing MDS SAN infrstructure already have 2 VSANs with ID number 4000 and 4001 ( Both of these VSANS are usied for some storage replication unrelated to UCS). In the UCS we alreay have 2 VSANS' ( 200 and 201) and are planning to create 2 more ( 300 and 301). My question is if I configure the FI's for F-port truncking/FC port channeling then what will happen to my existing VSAN 4000 and 4001 on the MDS9513 SAN
Thanks
RK

If you are asking how long it will take to enable f-port trunk and how disruptive it will be? It's not lengthy, but, it will cause the link to stop passing traffic and cause SCSI retrys. Your server will know it happened. If your fc multipathing is operating properly there will be no outage.If there are any configuration issues, the link may be down for an extended period, further compounding this disruption in traffic.
You initially asked about two features, f-port trunk and f-port channel. These are seperate features and require different configuration changes. It's best to add one feature at a time, not both in the same configuration change. Each change will be disruptive.
Do one fabric at a time. Ensure the f-port trunk is fully functional before doing the f-port channel, making sure it is functional before starting work on the second fabric.If your multipathing is operating as it should, there will be no outage. If there is any doubt schedule an outage window.
Dave

Port speed for ISL's and SP's , Hosts (MDS 9513)

Is there any recommendation/best practise for
1) setting port speed ie choose Auto or hard code eg 2gb, 4gb wrt b/w available ?
2) ratemode ie dedicated or shared ?
For ISL's And Storage processors/Controllers and hosts
Thanks,

For ISL's, if the line card is gen2, it must be configured as dedicated. For the port mode, I would recommend that you hard code the mode to E. I also like to code the speed on ISLs so that there is no chance that they would negotiate to a slower speed. IE: you don't want to have a 2GB link negotiate at 1GB.
As for storage controllers, depending on the fan in ratio, I would recommend hard coding them to the device speed, and if the port-group has the bandwidth available, make them dedicated.
As for hosts, they should be on the shared port, and I would leave them as port mode = auto. This way they can negotiate F or FL. You might want to configure a 'maximum allowable auto speed setting'.
IE: if your hosts have 2GB HBAs, and are plugged into a 4GB capable port, they will never negotiate to 4GB...so why have the MDS think it needs to keep some bandwidth for that port (in shared mode). I forget the command, but there is way to set auto-max for the port speed on shared ports.
Hope this helps,
Mike

Pruning ISL trunks question

Can you guys confirm this for me please ?
1. If I prune a vlan from an isl trunk when the end switch has no member ports, I will save isl encapsulated broadcast traffic from going across the trunk for this vlan ?
2. If I convert my trunks from isl to 802.1q I will save 26 bytes for each frame. Perhaps more because with 802.1q I could have a native non encapsulated vlan and save even more ?
Is this good practice ?
Thanks

Hi Friend,
1. Yes
2. ISL encapsulation does not have a concept of Native vlan so yes native vlan on dot1q trunk will not have any tagging and yes if you configure dot1q you will save a header of 26 bytes but dot1q also puts a internal tagging of 4 bytes.
Yes it is definetely a good practice because first dot1q is open standard and second farme size get reduced.
HTH, if yes please rate the post.
Ankur

Export AVI video trunked and "incompatible format" comes back with DSP

Hi all,
I'm trying to export a my digital video created with iMovie in AVI format, but the final video is trunked after 7 min. At the same time I tried to generate the .mov file and import it into DVD Studio Pro 4, but an "Incompatible format" comes me back. Help me!
Thanx a lot.

One thing to try is deleting preferences.
Home-library-preferences-imovie preferences
also, sometimes people start running out of hard drive space...is there enough room left?
Hugh

Adding ICT trunk and SIP trunk into Route group

Hi ,
We need to map ICT and SIP trunk into the same route group ,but the problem here is already same ICT is mapped to another route pattern.
If i try to create new ICT with same remote IP ,it's throwing Add failed because the remote IP is already defined.
Is there anyway we can add ICT with same remote IP and map the ICT and SIP trunk ? or Is there anyway that we can add exisitng ICT into route pattern.
Route pattern is used for this route group is different.CUCM version - 7.X.Please advice.
Regards,
Ramanathan

Thanks Suresh ...
In that case ,I can assign the route group(ICT ,SIP - Top Down) to two different Route pattern.
Both patterns will hit ICT first ,Please correct me if I am wrong.
Ram

VLAN Trunking and GVRP

Decided we'd give the Cisco 300 series switches a try and see
what we think about them compared to our Cisco Catalyst 2960 switches.
I'm already stumped on setting up VLAN trunking between 4 switches. Do I have to manually setup all the VLAN's on each switch? I set them up on the first switch and was expecting GVRP would propagate them to the others like VTP.
Denny

Decided we'd give the Cisco 300 series switches a try and see
what we think about them compared to our Cisco Catalyst 2960 switches.
I'm already stumped on setting up VLAN trunking between 4 switches. Do I have to manually setup all the VLAN's on each switch? I set them up on the first switch and was expecting GVRP would propagate them to the others like VTP.
Denny

Forwarding with SIP Trunking and Retaining CID

We are using SIP trunking to get to the PSTN and CUCM 7.1. The SIP provider only permits calls originating from their own DIDs.
So how can we allow our users to forward all calls to say their cell phone. AND when a call comes in we want them to be able to see the original caller ID. Is it possible? What is the mojo? Thanks!

Hi,
for the SIP trunks there are no limits from the system. Check this out: https://supportforums.cisco.com/message/3795863#3795863
If you have different voice codecs for your phones and the trunk you need DSP ressources for transcoding.
As I know the UC520 have a PVDM2-64 with 4 DSP chips. You can use the DSP calculator from cisco to find out how many DSPs you need. But keep in mind that conferencing and transcoding can't share a DSP processor.
For example 1 DSP for conferencing and 3 for transcoding.
best regards
Christian

Trunking and the management VLAN

I have gotten my 5010's up and can get to them from mgmt0. The ip address for mgmt0 resides in VLAN 2 for me. I am getting ready to trunk my 5010's back to my 6500's. Do I need to make sure that VLAN 2 cannot be seen through the trunk ports since it resides on mgmt0?

I don't think this is technically right- the MGMT and the data-path aren't actually connected. The MgmT 0 port doesn't have any concept that it's on "vlan 2"- it's just an access port.
Similarly, if VLAN 2 is on the trunk port, the IP address you assigned to MGMT0 isn't going to respond.
If you configured "feature interface vlan" and then put an IP address on VLAN 2, you could mange this box that way- on two separate IP addresses, via the two separate connections.
With the current lack of ability to wrap ACLs around the Interface VLANs, I'm more comfortable NOT using interface-vlan commands, and using a single uplink to mgmt0. Loss of the mgmt0 port is now only loss of the ability to manage the switch, not a data-path impacting event. (unless you need to configure the switch to correct an data-path issue, in which case you've got problems.)
The shift to out-of-band is a nice feature, but it's going to require a big shift in thinking from an implementation standpoint.

Trunk and channel problem

i have 2 4507s each with dual sup 4s. I have applied the below configs to them respectively. However, the interfaces both show down and down, any suggestions?
interface Port-channel1
description Connecting both buildings
switchport
switchport trunk encapsulation dot1q
switchport mode trunk
interface GigabitEthernet1/1
description Connection to building-1
switchport trunk encapsulation dot1q
switchport mode trunk
channel-protocol lacp
channel-group 1 mode active
interface GigabitEthernet2/1
description Connection to building-1
switchport trunk encapsulation dot1q
switchport mode trunk
channel-protocol lacp
channel-group 1 mode active
(2nd Switch)
interface Port-channel1
description Connecting both buildings
switchport
switchport trunk encapsulation dot1q
switchport mode trunk
interface GigabitEthernet1/1
description Connection to building-2
switchport trunk encapsulation dot1q
switchport mode trunk
channel-protocol lacp
channel-group 1 mode active
interface GigabitEthernet 2/1
description Connection to building-2
switchport trunk encapsulation dot1q
switchport mode trunk
channel-protocol lacp
channel-group 1 mode active

I noticed in your configs that there is a difference between both supervisors. The channel is configured on one module, shut on the otehr one. This may point to a redundancy issue. Looked up a URL on that as well:
http://www.cisco.com/en/US/products/hw/switches/ps4324/products_configuration_guide_chapter09186a00804d781c.html#wp1113491
Suggest that you check this first and bring your sup4's back in sunc if needed.
Leo

NexVortex SIP trunk and UC500 default timeout settings?

Hey guys,
I'm doing a little SIP trunk testing to determine a good provider for my customer base, and had some general questions as I can't seem to get outgoing or incoming phone calls to work at all.
To keep things simple, I'm using an 8user UC540W with 3 IP phones - a 525G, a 524G, and a 7937 conference phone. I have a static IP on the UC540, have run through the telephony wizard and everything seems to be working on the LAN/PBX side of things. The big difference, and the major variable that we are working with (I believe), is that we're working with Satellite internet connectivity rather than terrestrial Internet connectivity. This is an Enterprise satellite connection, and we have run voice over the connection without problems, but this is our first attempts at SIP trunking from a UC500. Due to the latency involved inherent in satellite (ping times around 550-700ms), I believe that either UC540 or NexVortex server/switch is timing out. Is there any way to determine what the default setting is for a SIP acknowledgement on the UC540 and change this if it is too small?
Here is what I have found, if it is helpful:
Outgoing calls:
1. The SIP provider, NexVortex, says that they are seeing an invite from the UC540, but not on port 5060. On the two calls that we tested, it first saw an invite on 63452, and then on 51677. Is there any reason why this would not be sent out on 5060?
Incomign calls:
1. On incoming calls, Nexvortex is routing the calls to the proper IP, but is then receiving an "error 500 reason Q850" from the UC540. What does this error mean?
I am also attaching my config in the event that it helps. When I look at the SIP trunk status in CCA, it does not show that registration is working, so I assume that's a good place to start.
Lastly, the guys over at NexVortex don't seem to run across the UC500 very often. If anybody has setup their UC500 to work with NexVortex and wouldn't mind posting a screenshot from CCA (feel free to remove usernames and passwords), I'd appreciate it. I'm not certain that I have all of the information in the right places.
Thanks,
Seth

Hi Steven,
Thanks for the continued help.
I was able to make the changes in the config. Here are snapshots from the current config:
dial-peer voice 1000 voip
description ** Incoming call from SIP trunk (Generic SIP Trunk Provider) **
voice-class codec 1
voice-class sip dtmf-relay force rtp-nte
session protocol sipv2
session target sip-server
incoming called-number .%
dtmf-relay rtp-nte
ip qos dscp cs5 media
ip qos dscp cs4 signaling
no vad
dial-peer voice 3000 voip
description IncomingSIP
translation-profile incoming IncomingSIP_Called_4
voice-class codec 1
voice-class sip dtmf-relay force rtp-nte
session protocol sipv2
session target sip-server
incoming called-number 14068906254$
dtmf-relay rtp-nte
ip qos dscp cs5 media
ip qos dscp cs4 signaling
no vad
dial-peer voice 3001 voip
description IncomingSIP2
translation-profile incoming IncomingSIP2_Called_5
voice-class codec 1
voice-class sip dtmf-relay force rtp-nte
session protocol sipv2
session target sip-server
incoming called-number 1406890624[2-3]$
dtmf-relay rtp-nte
ip qos dscp cs5 media
ip qos dscp cs4 signaling
no vad
dial-peer voice 3002 voip
incoming called-number 14068906254$
no dial-peer outbound status-check pots
sip-ua
authentication username nomadgcs password 7 *removed*
no remote-party-id
retry invite 2
retry register 10
timers connect 100
registrar ipv4:66.23.129.253:5060 expires 3600
sip-server ipv4:66.23.129.253:5060
connection-reuse
host-registrar
We are calling from within the 406 area code, so when we dial the number with the leading 406, we get a message saying "You don't need the area code" from the telephone company. When we dial this from a cell, we get the following:
1. 4068906254 - "All circuits are busy, please try your call again..."
2. 8906254 - rings once, then no sound, then disconnects after about 10 seconds.
I don't know if this would factor in at all, but our NexVortex account is setup to deliver 14068906254 to the UC500, but would NexVortex deliver the entire string of characters if it is only receiving 4068906254 or 8906254?
Thanks,
Seth

After Enabling trunking and two VLANs on switchports - clients don't receive IP Addresses

Hello all and thanks for your help and expertise. Here's my scenario:
I have approximately 35 Ruckus APs in a building which has multiple VLANs. The switches are Cisco 3560G. I want to segment the wireless traffic onto a dedicated wireless VLAN (218). I created two scopes in DHCP to service the APs and wireless clients. The APs should get their IP addresses on VLAN 1 (VLAN 1 scope in dhcp.) The clients should get their IP addresses on VLAN 218 (VLAN 218 scope in dhcp). I utilized the following commands to accomplish this goal, unsuccessfully.
Example: on port gi0/5
1 - switchport trunk encapsulation dot1q
2 - switchport mode trunk
3 - switchport mode access
4 - switchport trunk allowed vlan 1,218
Problems: 1) The APs are not getting an IP address on the default or native VLAN 1 unless I configure an IP Helper. Please note we have another building where a consultant set this configuration up (and it works) but I don't see an IP helper set when I check the config for VLAN 1.
2) The wireless clients do not get an IP address on VLAN 218, even if I set an IP helper address. In the other building - there is an IP helper set on VLAN 218 so I'm not sure what I missing or if something else is configured.
I would greatly, greatly appreciate if someone could tell me what I'm missing here. Is there something else I have to do to ensure clients on vlan 1 and 218 are able to obtain dhcp addresses in the config of the switch? Do I have to further configure vlan 1 or 218? I'm enabling the correct encapsulation, trunking the ports, and setting the vlans. What am I missing here relative to APs and clients getting dhcp addresses. Anyway your help is much apprecaited.

You need vlan 218 on all switches and allowed on all trunks that need to pass traffic for that vlan.
You don't have to add it explicitly to STP as it should be run anyway but if you manually set STP priorities for other vlans you should probably do if for this vlan as well.
Shouldn't stop it working though.
If you manually assign a vlan 218 IP to a client can it ping the SVI IP ie. it's default gateway and if so can it ping devices in other vlans ?
Jon

Switch sg 200 trunk and DGateway query

hello
i'm using cisco sg 200 switches(24port ,48 port with 2 GBIC (rj-45 port and spf port) on each). in a small office network.i've attached the diagram.
please answer the below queries.
1)what should be the default gateway for both switches(coz im not using any router).
2)all the pc's are in workgroup.no Server.
3)i have connected the two switches using a crossover at gbic(rj45-port).and the remaining are straight connection from switch to all pc.what should i do inorder to config the trunk port.
as there are small series switches. there is no con port? and when i access the switch using the device ip there is no option to config default-gateway in that.
and on pc's i have enter the device ip as default gateway. only few pc's can ping each other. rest are not successful in getting the ping reply.
plz replly

Is it correct you have no configuration on the switches?
Do you have Internet or other networks that need to be reached or you just want all workstations to reach each other?
You do not need or want a default gateway if all workstations are assigned ip addresses is the same subnet.

Trunks going to non-trunk and flapping

Last week I had an issue where users were having trouble connecting to devices, interruptions, etc. I noticed some host flapping on quite a few ports in our engineering lab which looks to be a loop. I'm trying to figure out where/how this started. The confusion lasted for a few hours and then was gone. Why would we have ports go to non trunks after a loop? Our trunks are setup statically with a "switchport mode trunk". I could see this if DTP was negotiating. Also, why so many different ports flapping? I have seen this on at least 4 switches.
7/18/2014 10:52:34 AM 10.20.2.7 Warning 1892: 001919:   Host 00:1B:78:BC:A2:C6 in vlan 112 is flapping between port Gi1/1 and port Gi4/11
7/18/2014 10:52:32 AM 10.20.2.7 Warning 1891: 001918:   Host 00:50:56:A7:14:6F in vlan 112 is flapping between port Gi1/1 and port Gi2/5
7/18/2014 10:51:56 AM 10.20.2.7 Warning 1890: 001917:   Host 00:12:79:D5:E3:B3 in vlan 112 is flapping between port Gi1/1 and port Gi3/21
7/18/2014 10:51:56 AM 10.20.2.7 Warning 1889: 001916:   Host 00:50:56:A8:4C:D7 in vlan 112 is flapping between port Gi1/1 and port Gi4/11
7/18/2014 10:51:45 AM 10.20.2.7 Warning 1882: 001909:   Host 00:50:56:8E:5F:60 in vlan 112 is flapping between port Gi2/5 and port Gi1/1
7/18/2014 10:51:45 AM 10.20.2.7 Warning 1881: 001908:   Host 98:4B:E1:75:E4:48 in vlan 112 is flapping between port Gi3/32 and port Gi1/1
7/18/2014 10:51:42 AM 10.20.2.7 Warning 1880: 001907:   Host 00:11:43:DC:0E:EB in vlan 112 is flapping between port Gi1/1 and port Gi2/7
7/18/2014 10:51:41 AM 10.20.2.7 Warning 1879: 001906:   Host 10:60:4B:A9:81:8C in vlan 112 is flapping between port Gi1/1 and port Gi3/32
7/18/2014 10:51:38 AM 10.20.2.7 Warning 1878: 001905:   Host 00:12:79:D5:E3:B3 in vlan 112 is flapping between port Gi1/1 and port Gi3/21
000737: Jul 18 10:52:38.076 MDT: %SW_MATM-4-MACFLAP_NOTIF: Host 0050.5649.6d62 in vlan 112 is flapping between port Gi0/38 and port Po10
000738: Jul 18 10:52:39.091 MDT: %SW_MATM-4-MACFLAP_NOTIF: Host 0011.0a57.9382 in vlan 112 is flapping between port Po10 and port Gi0/6
000739: Jul 18 10:52:44.125 MDT: %SW_MATM-4-MACFLAP_NOTIF: Host 00c0.dd0c.b551 in vlan 112 is flapping between port Gi0/40 and port Po10
000740: Jul 18 10:52:48.092 MDT: %SW_MATM-4-MACFLAP_NOTIF: Host 0050.5649.6d62 in vlan 112 is flapping between port Gi0/38 and port Po10
000741: Jul 18 10:52:52.270 MDT: %SW_MATM-4-MACFLAP_NOTIF: Host 0050.564e.4e8e in vlan 112 is flapping between port Gi0/37 and port Po10
000742: Jul 18 10:52:52.907 MDT: %SW_MATM-4-MACFLAP_NOTIF: Host 0050.5647.3916 in vlan 112 is flapping between port Gi0/11 and port Po10
7/18/2014 4:45:16 PM 10.20.2.7 Notice 2056: 002085:   Port Gi2/46 has become non-trunk
7/18/2014 1:50:49 PM 10.20.2.7 Notice 2032: 002061:   Port Gi2/1 has become non-trunk
7/18/2014 1:50:41 PM 10.20.2.7 Notice 2029: 002058:   Port Gi2/4 has become non-trunk
7/18/2014 1:50:14 PM 10.20.2.7 Notice 2026: 002055:   Port Gi2/2 has become non-trunk
7/18/2014 1:49:42 PM 10.20.2.7 Notice 2017: 002046:   Port Gi3/6 has become non-trunk
7/18/2014 1:49:32 PM 10.20.2.7 Notice 2014: 002043:   Port Gi3/4 has become non-trunk
Thanks

Host flap can be a difficult symptom to resolve. It may be a cause from several different issues
- Do you have spanning tree enabled? If not, enable RSTP and ensure PORT FAST is not enabled on any switch interconnecting interface
- Do you have multiple gateways? It's possible a device is replicating a default gateway causing the source MAC to advertise 2 different way
-Do you have multiple DHCP pools from different sources? May be possible bleed over causing confusion
-We notice there are several ports, shut down every port then turn up one of the ports and see if the flap stops or not, this will help get you to find where a possible loop is at
-Are you load balancing over a LAG or something else, especially with servers? If load balancing with servers, make sure each NIC uses a different MAC or shut down one NIC for testing.

ISL trunking and MTU and PMTUD

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