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Cisco IOS Hints and Tricks: TRILL and 802.1aq are like apples and oranges A comment by Brad Hedlund has sent me studying the differences between TRILL and 802.1aq and one of the first articles I’ve stumbled upon was a nice overview which claimed that the protocols are very similar (as they both use IS-IS to select shortest path across the network). After studying whatever sparse information there is on 802.1aq (you might want to read Greg Ferro’s fascination with IEEE paywall) and the obligatory headache, I’ve figured out that the two proposals have completely different forwarding paradigms. To claim they’re similar is the same as saying DECnet phase V and MPLS Traffic Engineering are similar because they both use IS-IS. TRILL forwarding Within the backbone, TRILL is a true layer-3 protocol: TRILL header has a hop count, RBridges have layer-3 addresses and the layer-2 header changes as the packet is propagated across the backbone. 802.1aq forwarding The ingress PBB (Provider Backbone Bridge) takes the user’s MAC frame and encapsulates it in 802.1ah MAC frame.
GNS3 | Graphical Network Simulator wiki:vpcs [Who Is Wiki] The VPCS can simulate up to 9 PCs. You can ping/traceroute them, or ping/traceroute the other hosts/routers from the virtual PCs when you study the Cisco routers in the Dynamips. VPCS is not the traditional PC, it is just a program running on the Linux or Windows, and only few network commands can be used in it. But VPCS can give you a big hand when you study the Cisco devices in the Dynamips. Try VPCS, it can save your CPU/Memory. Now, VPCS can be run in udp or ether mode. Download The latest version 0.21a , download from sourceforge , or download here has been tested under CentOS64/Ubuntu64/OSX/WindowsXP/Windows7. Usage vpcs [options] -u udp mode, default -e tap mode, using /dev/tapx -s port local udp port, default from 20000 -c port remote udp port(dynamips udp ports), default from 30000 -r file run startup file If in the ether mode, please run it before the dynamips loads/starts the ios. .net file (ether mode), please refer to dynagen for details. .bat (udp mode) .net file (udp mode) Note
Route Views Project Page Internetworking Technology Handbook From DocWiki Creating a PDF of the Internetworking Technology Handbook Create a PDF of the Internetworking Technology Handbook that you can save on your computer and print. Internetworking Basics An internetwork is a collection of individual networks, connected by intermediate networking devices, that functions as a single large network. The following articles provide information about internetworking basics: LAN Technologies A LAN is a high-speed data network that covers a relatively small geographic area. The following articles provide information different LAN technologies: WAN Technologies A WAN is a data communications network that covers a relatively broad geographic area and that often uses transmission facilities provided by common carriers, such as telephone companies. The following articles provide information about the various protocols and technologies used in WAN environments: Internet Protocols The following articles provide information about different IOS IP technologies: Routing
VirtualBox The PDU Exchange - Yet Another Cisco Blog... AAA and VTYs in IOS-XR : Bingo Continuing on the IOS-XR saga, this is the newest bunch of things that don't "work as expected" (© Cisco). Well, as expected by me, not by Cisco. Everything started while trying to configure a primary and backup aaa login method on an ASR9k, when i realized that... 1) having a backup aaa login method with the same tacacs servers as the ones in the primary aaa login method (which is using the management vrf) doesn't work Imagine the following aaa configuration: ! This is supposed to work in the following way: As long as at least one mgmt interface is up (i'm using a virtual-ip for the mgmt interfaces), tacacs communication should happen through the out-of-band mgmt interfaces. Guess what! In order to overcome the above problem, i thought of using different vty templates, each one with a different access method. ! Since the "rotary" command is not supported in IOS-XR, this is what you can do: ! And this is the point you realize that you can't choose a vty, because... So i tried the following: !