Posted on in Networking
DS3 (also known as T3) scrambling is not an issue that comes up very often. It's something every network administrator should know about, though. After all, it just might save your bacon.
Some physical layer protocols depend on the transition from 1 to 0 in a frame to maintain clocking …
Posted on in Networking
Is your network bandwidth being consumed by Peer-to-Peer (P2P) traffic? (Hint: If you don't know, it's time to fire up NBAR and do a little investigating.) One way to stop P2P traffic is to use an access-list to block traffic on the well-know P2P ports. Unfortunately, many P2P technologies no …
Posted on in Networking
Deciding whether to use <acronym title="Remote Authentication Dial-In User Service">RADIUS</acronym> or <acronym title="Terminal Access Controller Access Control System Plus">TACACS+</acronym> for <acronym title="Authentication, Authorization, Accounting">AAA</acronym> functionality on a Cisco-based network seems straight-forward. After all, if the network uses Cisco, shouldn't the AAA …
Posted on in Networking
<acronym title="UniDirectional Link Detection">UDLD</acronym> is a Cisco protocol designed to detect and disable unidirectional links in Ethernet (fiber or twisted-pair). In the case of a radio-based Metro Ethernet ring, UDLD goes the extra mile in preventing Spanning-Tree loops and user service interruption.
In this simple network of …
Posted on in Networking
It used to be that access lists in Cisco IOS were numbered. Not only were they numbered, but the numbers were significant to what kind of access list they were. Now access lists (and just about everything else) can be named rather than numbered. Although this seemingly innocuous change has …
