How many time have you wanted to know how long a cable run was? Now if you are running cisco 3750 switches you can find out by issuing the following commands you can see how long that cable run really is.

Switch# test cable-diagnostics tdr interface gigabitethernet0/2
TDR test started on interface Gi0/2

A TDR test can take a few seconds to run on an interface. Use "show cable-diagnostics tdr" to read the TDR results.

Switch#show cable-diagnostics tdr interface gigabitEthernet 0/2
TDR test last run on: Dec 10 09:05:10

         Interface Speed Local pair Pair length Remote pair Pair status
         --------- ------ ---------- ------------ ------------ ----------
         Gi0/2 auto Pair A   22 +/- 4 m N/A Open
           Pair B    21 +/- 4 m N/A Open
           Pair C    5 +/- 4 m N/A Open
           Pair D    20 +/- 4 m N/A Open

I recently decided to plug my wic-1adsl card into a 3640 router because my 2620 had a power supply failure. I noticed that the cisco 3640 ran very slow, and speed tests topped out at 2.6mbps downlink speeds. For a while I couldn’t figure out why a router that is faster with more memory would run slower than my 2620 router. I later discovered the reason for the slowness was because of a bandwidth limit on the nm-1fe1r2w card I was using to give me wic slots. (more…)

 The Cisco IOS has many powerful security features that enable network engineers to protect their internal network. The Cisco IOS is capable of intrusion detection, deep packet inspection, and stateful firewall features. Setting up IPS allows the admin to push intrusion detection to the network edge. The Cisco IPS feature set can scan for spyware, viruses, worms, Trojans, and network intrusions by receiving updated signature files from Cisco. If a packet or series of packets matches a particular signature the router can, send an alert, drop the packet, or reset the connection of the offending user. In this way the network engineer can better protect the network by acting on suspicious packets before they can pose a risk to the network infrastructure, another advantage of pushing IPS duties to the network edge is it allows offending packets to be dropped before they take up finite network resources.  In large networks as much as 10 percent of network resources could be consumed by packets that ultimately will be dropped for security reasons deeper in the network. (more…)

This config is for the Cisco 1800 series router running IOS 12.4. IOS 12.4 has some command and syntax changes in reguards to interfaces and configuration commands for PPPOE. This config was submitted by my good friend Pedro Rivera.

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Configuring a Cisco router to use the WIC-1ADSL card is one of the most commonly asked question by people in the Cisco forums. There are some interesting and compelling reasons to use a WIC card instead of connecting PPPOE through the ADSL modem in bridged mode. One of the most compelling reasons is the ability to use advanced QOS features such as interleaving and fragmentation. Because the DSL WIC card shows up as an ATM WAN interface, the router is able to perform those advanced Quality of Service features.  The overhead of encapsulating a packet in PPPOE and sending it to the modem over some length of cable is also a reason to use a WIC card instead of the modem.

It is important to realize that with most ISP’s you can configure the connection to use either PPPOA or PPPOE, the difference in configuration is very subtle however it can save you a couple of bits of overhead as PPPOE is encapsulated more time Than PPPOA.  So without further a due: (more…)