FirstDigest » Network Services

Cisco QoS at-a-glance

Calin — Fri, 08 Jul 2011 12:49:43 +0000

Stephan, a colleague of mine, found the following documents digging through multiple pages of Cisco.com. The documents present a nice view of different QoS approaches and the most important information. Somehow like “cheatsheets”. They were helpful to us when need to implement QoS in some parts of the network that we administer. I hope they will help you as well.

Maybe you are wondering why I’m adding them here, since the documents are already somewhere in Cisco.com. As probably you [...]

Cisco: Prioritize Voice traffic with LLQ

Calin — Wed, 19 May 2010 11:45:56 +0000

In one of my previous posts I was explaining how to mark packets closer to network edge. Starting from that point, we are sure the packets are market with the correct value, so on the router device we can directly match those packets and prioritize using Low Latency Queueing.

I believe you already know why queueing is so important for Voice packet especially, but also for all other kind of real time protocol [...]

Cisco: Mark voice packets at the network edge

Calin — Tue, 04 May 2010 20:50:15 +0000

You know how Cisco always advise to mark the packet as close to the your network edge as you can? Even more you can find a lot of example where Cisco show how to trust the packets directly on the access switch, but not all the time you can do this.

First because not everybody has devices that mark correct packets (like Cisco IP Phones) but we still have to [...]

Cisco AutoQoS VoIP

Calin — Thu, 19 Nov 2009 22:22:58 +0000

QoS – one of the most interesting and challenging part of the network engineer’s life. I think I’m not wrong when I’m saying that most engineers that hear the word QoS, react somehow like “ah, that ugly stuff…” I have to be honest and say that QoS is not one of my preferred part, but as a network engineer you have to accomplish all task, not only the one that you like. With QoS you can achieve some great results, and once you have started [...]

Cisco: How to shape traffic on Frame-Relay connection

Calin — Thu, 12 Mar 2009 09:50:23 +0000

In some previous article, I explained how to configure a Frame-Relay Hub and Spoke network environment. Based on that example, I will show you today how you can implement traffic shaping over the Frame-Relay Hub and Spoke.You can have a look at the topology that we will use here.

A note from the beginning. Since I do not have [...]

Cisco: How to use kron to automate tasks

Calin — Fri, 27 Feb 2009 13:33:43 +0000

Now and then everybody in IT network industry has to stay awake over the night to accomplish some tasks that cannot be performed during the work hours because will disturb regular activity. Some of this task usually need your presence in field (virtually or in place), to assure that everything is working fine and you don’t have any unwanted surprise the next day.Skipping this tasks, there are other ones with less impact in case of a failure, which I believe you rather prefer to do [...]

Cisco: How-to get notifications for IP SLA monitor using EEM

Calin — Sat, 07 Feb 2009 22:59:39 +0000

In some previous post, I explained how to configure a basic IP SLA monitor for checking the round-trip time between two Cisco routers. Because in the comments of that post I have been asked how you can get e-mail notification for IP SLA monitor, I have decided to write another post to extend a little bit this topic.

To accomplish e-mail notification for IP SLA monitors we will use [...]

Cisco: How to configure simple IP SLA monitor

Calin — Tue, 16 Dec 2008 20:49:11 +0000

Before we begin let’s see what is this SLA term, for those of us who are not very familiar with the Service Provider terms. IP Service Level Agreements (SLAs) enable customers to assure new business-critical IP applications, as well as IP services that utilize data, voice, and video, in an IP network. With Cisco IOS IP SLAs, users can verify service guarantees, increase network reliability by validating network performance, pro actively identify network issues assure an easy way to deploy new IP services. Cisco IOS [...]

Cisco: Very simple NTP configuration

Calin — Wed, 03 Dec 2008 14:46:23 +0000

NTP (Network Time Protocol) is usually very simple to configure on Cisco devices. Of course you can reach complex configuration, but since I work in this field I didn’t saw somebody to push the things to extreme in NTP configuration.

NTP is based on server – client relation. It is recommended that in a Cisco network environment, you should use online the client part of the NTP, and to choose some external NTP sever to synchronize with. This is because using a NTP server (master) [...]

Cisco: Packet sniffing

Calin — Wed, 26 Nov 2008 09:05:16 +0000

The official term of Cisco for Packet sniffing is SPAN ( Switched Port Analyzer ) also called sometimes port mirroring or port monitoring and it’s purpose is to select traffic from a source and send to a destination with a network analyzer tool. You can find out there terms like RSPAN, PSPAN, VSPAN, ESPAN, but this are at their basic functionality nothing more than SPAN with some enhanced features ( e.g. ESPAN – Enhanced SPAN ) or describing their primary functionality ( e.g. VSPAN – [...]