RE: tagged vs. untagged VLAN
-Original Message- From: Jay Nakamura [mailto:zeusda...@gmail.com] Sent: den 29 september 2010 03:28 To: NANOG Subject: tagged vs. untagged VLAN >In a SP environment, you need to hand off two VLANs to a customer, is >there any advantage or disadvantage in doing the following two setups? > >- One untagged and one tagged VLAN >- Two tagged VLAN and no untagged VLAN > >I can't think of anything other than some equipment may not let you >have no untagged VLAN. But it's bugging me that something could go >wrong by not having untagged native VLAN that I can't think of. I would go with tagged for both VLANs. If you can't tag the native in your equipment create a dummy VLAN and use it as native on the link and all VLANs will be tagged. If you know the customer will be using more VLANs later on Q-in-Q might be a good solution or you will have to transport a lot of VLANs in your network and they might collide with other customers etc. /Daniel
RE: The tale of a single MAC
On Mon, jan 03, 2011 at 07:05:24, Mikael Abrahamsson wrote: > Subject: Re: The tale of a single MAC > > On Mon, 3 Jan 2011, Dobbins, Roland wrote: > > > I remember that there were several high-profile instances of > duplicate > > MAC addresses being burnt into NICs during the 1990s - once every > > 2-3 years, IIRC. And those were just the ones that were discussed > publicly. > > D-Link shipped NAT-boxes around 2003-2004 or so with identical MAC > addresses (and a "clone your PC mac address to the WAN interface"- > functionality). I checked my then employer ADSL network and 5% of the > customer ports had the same MAC address, D-Link support alledgedly > said something about the MAC address not being "unique enough" and > directed their customers to the cloning functionality to "solve" the problem. > > -- > Mikael Abrahamssonemail: swm...@swm.pp.se Years ago D-link and Linksys and maybe other vendors used the source MAC of 00:00:00:00:00:00 which isn't very nice and could cause interesting issues. At my current job we used to have a routine to find these MACs and tell the users to change to a valid address.
SV: Advice regarding Cisco/Juniper/HP
> in closing, i have to say I love HP's "alias" command, I can rev my > config and save it to a tftp server by typing "saveit" while enabled. > Some IOS's allow you to do a "wr net" and get it there with a predefined > tftp server, but as we discovered, this isn't available on all devices.. > take care and have a great weekend, > greg You can use alias for Cisco as well but default is to ask for TFTP IP etc but you can change this with file prompt quiet. Then you can do copy run tftp://1.2.3.4/router-conf and make an alias for that. Or you could write it in EEM like I did, you can trigger to save when someone changed the config or at a certain time etc. You could also use the archive command to upload configs. /Daniel
