ISL is Cisco proprietary and uses an encapsulation around the frame and does not modify the Ethernet frame. 802.1Q is IEEE standard and uses frame tagging and it modifies the Ethernet frame. ISL also allows you to violate the Ethernet MTU size because it encapsulates the frame and does not alter the frame. I hope this helps!
Daniel Ladrach CCNA, CCNP WorldCom -----Original Message----- From: Kaminski, Shawn G [mailto:[EMAIL PROTECTED]] Sent: Monday, March 11, 2002 9:59 AM To: [EMAIL PROTECTED] Subject: ISL or 802.1q? [7:37859] Repost. First one didn't make it. > -----Original Message----- > From: Kaminski, Shawn G > Sent: Friday, March 08, 2002 2:54 PM > To: 'Groupstudy' > Subject: ISL or 802.1q? > > After a search of the archives and reading the posts, I realize this has > been discussed before. I also searched CCO. However, there didn't seem to > be a clear answer on what I was looking for. We have two Distribution > Cisco 6509 switches trunked together and there is an argument as to > whether we should use ISL or 802.1q on this trunk. Our network is all > Cisco. Some people are saying 802.1q on everything because Cisco is > leaning towards this direction anyway. Some say ISL should be used between > the Distribution switches and 802.1q between Distribution and Access > switches. I don't know why because I couldn't find anything on this. Some > of the people here keep saying that ISL has more "features" than 802.1q. > Could some of you please give your opinions about what you would use (ISL > or 802.1q) in this situation? > > Thanks, > Shawn G. Kaminski > EDS Network Engineering - DowNET Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=37869&t=37859 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
