Re: ARP issue with 802.1q Trunking
Keep in mind, by default the switch will not tag the Native VLAN which is VLAN 1 by default. You will need to adjust the configuration of the router accordingly. See the following sample configuration for more details: http://www.cisco.com/warp/customer/473/50.shtml Sample Configuration: ISL/802.1Q Trunking Between a Catalyst 2900XL/3500XL and a Cisco 2600 Router -- Richard Froom CCIE# 5102 [EMAIL PROTECTED] 919-392-2136 "Brian" [EMAIL PROTECTED] wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... with dot1q, I make my first vlan #2, I have had problems with vlan #1, it may be the way dot1q treats vlan #1 and what it expects to be in there. Brian On Tue, 20 Feb 2001, John Neiberger wrote: I have a 2620 connected to a 2924XL using ISL trunking. Three VLANs configured on both sides, VLAN 1 is the management VLAN. I can ping from the router to the switch and vice versa. Now, I changed the encapulation type on both sides to dot1q and communication breaks. Turning on debugging, I found the following problem. Apparently, the 2620 is throwing out the ARP replies from the switch. Here is the output from debup arp: 00:15:09: IP ARP: sent req src 10.16.102.70 0030.8546.b740, dst 10.16.102.16 .. FastEthernet0/0.1 00:15:09: IP ARP: sent req src 10.16.102.70 0030.8546.b740, dst 10.16.102.16 .. FastEthernet0/0.1 00:15:09: IP ARP rep filtered src 10.16.102.16 0005.3214.99c0, dst 10.16.102.70 0030.8546.b740 wrong cable, interface FastEthernet0/0 00:15:09: IP ARP rep filtered src 10.16.102.16 0005.3214.99c0, dst 10.16.102.70 0030.8546.b740 wrong cable, interface FastEthernet0/0 What the heck does wrong cable mean? The only potential problem I see is that it is sending the ARP request out fa0/0.1, but receiving the reply on fa0/0. Is there some configuration step that I'm missing? I've never tried to configure dot1q before, but it seems to me that if the native vlan is the same on both sides that the only configuration difference would be the encapsulation type on each side. Can any of you provide any advice concerning this? And changing back to ISL isn't going to solve my problem because I'm just playing around and I want to make this work! :-) Thanks, John _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] --- I'm buying used CISCO gear!! email me for a quote Brian Feeny e:[EMAIL PROTECTED] CCNP+Voice/ATM/Security p:318.222.2638x109 CCDP f:318.221.6612 Network Administrator ShreveNet Inc. (ASN 11881) _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: ARP issue with 802.1q Trunking (resolved)
I just figured it out. There is a "feature" that was supposed to be fixed on the 2600 in this release, but it was not. I'm running 12.1(5) and they say this problem was fixed in anything after 12.1(3). Back then, the native VLAN IP address had to be configured on the major interface, not on a subinterface. I removed the subinterface for VLAN 1 and configured it on the major interface and everything works great. If I upgrade to 12.1(6), I would have to go back to the normal method, placing the native VLAN on a subinterface like all the others. Regards, John "Tim O'Brien" [EMAIL PROTECTED] 2/20/01 1:12:53 PM That is very weird. Have you tried changing the encapsulation type and then rebooting both of the boxes to clear any "remains" out? Tim - Original Message - From: "John Neiberger" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, February 20, 2001 2:57 PM Subject: Re: ARP issue with 802.1q Trunking Unfortunately, that doesn't even make sense in this scenario. I'm using a straight-through cable from the router to the switch, and ISL trunking is working great. I only get that error when I change the encapsulation type. Weird, huh? thanks, John "Tim O'Brien" [EMAIL PROTECTED] 2/20/01 12:54:05 PM The only thing that I could find is "Verify the cable selection (crossover versus non-crossover)". Tim - Original Message - From: "John Neiberger" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, February 20, 2001 2:25 PM Subject: ARP issue with 802.1q Trunking I have a 2620 connected to a 2924XL using ISL trunking. Three VLANs configured on both sides, VLAN 1 is the management VLAN. I can ping from the router to the switch and vice versa. Now, I changed the encapulation type on both sides to dot1q and communication breaks. Turning on debugging, I found the following problem. Apparently, the 2620 is throwing out the ARP replies from the switch. Here is the output from debup arp: 00:15:09: IP ARP: sent req src 10.16.102.70 0030.8546.b740, dst 10.16.102.16 .. FastEthernet0/0.1 00:15:09: IP ARP: sent req src 10.16.102.70 0030.8546.b740, dst 10.16.102.16 .. FastEthernet0/0.1 00:15:09: IP ARP rep filtered src 10.16.102.16 0005.3214.99c0, dst 10.16.102.70 0030.8546.b740 wrong cable, interface FastEthernet0/0 00:15:09: IP ARP rep filtered src 10.16.102.16 0005.3214.99c0, dst 10.16.102.70 0030.8546.b740 wrong cable, interface FastEthernet0/0 What the heck does wrong cable mean? The only potential problem I see is that it is sending the ARP request out fa0/0.1, but receiving the reply on fa0/0. Is there some configuration step that I'm missing? I've never tried to configure dot1q before, but it seems to me that if the native vlan is the same on both sides that the only configuration difference would be the encapsulation type on each side. Can any of you provide any advice concerning this? And changing back to ISL isn't going to solve my problem because I'm just playing around and I want to make this work! :-) Thanks, John _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: ARP issue with 802.1q Trunking
with dot1q, I make my first vlan #2, I have had problems with vlan #1, it may be the way dot1q treats vlan #1 and what it expects to be in there. Brian On Tue, 20 Feb 2001, John Neiberger wrote: I have a 2620 connected to a 2924XL using ISL trunking. Three VLANs configured on both sides, VLAN 1 is the management VLAN. I can ping from the router to the switch and vice versa. Now, I changed the encapulation type on both sides to dot1q and communication breaks. Turning on debugging, I found the following problem. Apparently, the 2620 is throwing out the ARP replies from the switch. Here is the output from debup arp: 00:15:09: IP ARP: sent req src 10.16.102.70 0030.8546.b740, dst 10.16.102.16 .. FastEthernet0/0.1 00:15:09: IP ARP: sent req src 10.16.102.70 0030.8546.b740, dst 10.16.102.16 .. FastEthernet0/0.1 00:15:09: IP ARP rep filtered src 10.16.102.16 0005.3214.99c0, dst 10.16.102.70 0030.8546.b740 wrong cable, interface FastEthernet0/0 00:15:09: IP ARP rep filtered src 10.16.102.16 0005.3214.99c0, dst 10.16.102.70 0030.8546.b740 wrong cable, interface FastEthernet0/0 What the heck does wrong cable mean? The only potential problem I see is that it is sending the ARP request out fa0/0.1, but receiving the reply on fa0/0. Is there some configuration step that I'm missing? I've never tried to configure dot1q before, but it seems to me that if the native vlan is the same on both sides that the only configuration difference would be the encapsulation type on each side. Can any of you provide any advice concerning this? And changing back to ISL isn't going to solve my problem because I'm just playing around and I want to make this work! :-) Thanks, John _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] --- I'm buying used CISCO gear!! email me for a quote Brian Feeny e:[EMAIL PROTECTED] CCNP+Voice/ATM/Security p:318.222.2638x109 CCDPf:318.221.6612 Network Administrator ShreveNet Inc. (ASN 11881) _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: ARP issue with 802.1q Trunking (resolved)
Also be aware that running CEF on the fastethernet interface is problematic with dot1q. Some versions of IOS specifically have it shut off, others have it on. If you have global cef on "ip cef", then be carefull. Brian On Tue, 20 Feb 2001, John Neiberger wrote: I just figured it out. There is a "feature" that was supposed to be fixed on the 2600 in this release, but it was not. I'm running 12.1(5) and they say this problem was fixed in anything after 12.1(3). Back then, the native VLAN IP address had to be configured on the major interface, not on a subinterface. I removed the subinterface for VLAN 1 and configured it on the major interface and everything works great. If I upgrade to 12.1(6), I would have to go back to the normal method, placing the native VLAN on a subinterface like all the others. Regards, John "Tim O'Brien" [EMAIL PROTECTED] 2/20/01 1:12:53 PM That is very weird. Have you tried changing the encapsulation type and then rebooting both of the boxes to clear any "remains" out? Tim - Original Message - From: "John Neiberger" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, February 20, 2001 2:57 PM Subject: Re: ARP issue with 802.1q Trunking Unfortunately, that doesn't even make sense in this scenario. I'm using a straight-through cable from the router to the switch, and ISL trunking is working great. I only get that error when I change the encapsulation type. Weird, huh? thanks, John "Tim O'Brien" [EMAIL PROTECTED] 2/20/01 12:54:05 PM The only thing that I could find is "Verify the cable selection (crossover versus non-crossover)". Tim - Original Message - From: "John Neiberger" [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, February 20, 2001 2:25 PM Subject: ARP issue with 802.1q Trunking I have a 2620 connected to a 2924XL using ISL trunking. Three VLANs configured on both sides, VLAN 1 is the management VLAN. I can ping from the router to the switch and vice versa. Now, I changed the encapulation type on both sides to dot1q and communication breaks. Turning on debugging, I found the following problem. Apparently, the 2620 is throwing out the ARP replies from the switch. Here is the output from debup arp: 00:15:09: IP ARP: sent req src 10.16.102.70 0030.8546.b740, dst 10.16.102.16 .. FastEthernet0/0.1 00:15:09: IP ARP: sent req src 10.16.102.70 0030.8546.b740, dst 10.16.102.16 .. FastEthernet0/0.1 00:15:09: IP ARP rep filtered src 10.16.102.16 0005.3214.99c0, dst 10.16.102.70 0030.8546.b740 wrong cable, interface FastEthernet0/0 00:15:09: IP ARP rep filtered src 10.16.102.16 0005.3214.99c0, dst 10.16.102.70 0030.8546.b740 wrong cable, interface FastEthernet0/0 What the heck does wrong cable mean? The only potential problem I see is that it is sending the ARP request out fa0/0.1, but receiving the reply on fa0/0. Is there some configuration step that I'm missing? I've never tried to configure dot1q before, but it seems to me that if the native vlan is the same on both sides that the only configuration difference would be the encapsulation type on each side. Can any of you provide any advice concerning this? And changing back to ISL isn't going to solve my problem because I'm just playing around and I want to make this work! :-) Thanks, John _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] --- I'm buying used CISCO gear!! email me for a quote Brian Feeny e:[EMAIL PROTECTED] CCNP+Voice/ATM/Security p:318.222.2638x109 CCDPf:318.221.6612 Network Administrator ShreveNet Inc. (ASN 11881) _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
