Network technologies and trends

October 14, 2014  6:42 AM

What is Route Dampening?

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

In order to reduce the propagation of unstable routes also known as flapping routes, in BGP Protocol one can use the BGP feature called Route dampening. A route is considered to be flapping when its availability alternates repeatedly. Since BGP routing tables are huge, it’s not practical send those routing updates to all the routers especially when a route flap occurs. This could affect the performance of the network as well as consume more routers resources like CPU.

When a prefix flaps it will be assigned a penalty of 1000 and moved into the dampening state “history”. Each flap incurs another penalty (of 1000), which is applied cumulatively. If the penalty reaches the suppress-limit, the route is dampened, meaning it won’t be advertised to any neighbours.

BGP Route Dampening Terms:

  • Flap—A route whose availability alternates repeatedly
  • History state—After a route flaps once, it is assigned a penalty and put into history state, meaning the router does not have the best path, based on historical information.
  • Penalty—Each time a route flaps, the router configured for route dampening in another autonomous system assigns the route a penalty of 1000. Penalties are cumulative. The penalty for the route is stored in the BGP routing table until the penalty exceeds the suppress limit. At that point, the route state changes from history to damp.
  • Damp state—In this state, the route has flapped so often that the router will not advertise this route to BGP neighbours
  • Suppress limit—A route is suppressed when its penalty exceeds this limit. The default value is 2000
  • Half-life—Once the route has been assigned a penalty, the penalty is decreased by half after the half-life period (which is 15 minutes by default). The process of reducing the penalty happens every 5 seconds.
  • Reuse limit—As the penalty for a flapping route decreases and falls below this reuse limit, the route is unsuppressed. That is, the route is added back to the BGP table and once again used for forwarding. The default reuse limit is 750. The process of un suppressing routes occurs at 10-second increments. Every 10 seconds, the router finds out which routes are now unsuppressed and advertises them to the world
  • Maximum suppress limit—This value is the maximum amount of time a route can be suppressed. The default value is four times the half-life.

BGP Route dampening is one of the keys topics covered for Cisco CCIE Routing and Switching exam, so its better to understand the concept of Route Dampening and how it can configured in real networks. In upcoming post I will demonstrate how to configure Route Dampening on Cisco Routers.

October 2, 2014  5:31 AM

A review for “CCIE Routing and Switching v5.0 Official Cert Guide Vol 1″

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

I have been waiting eagerly and patiently for the release of the title CCIE Routing and Switching v5.0 Official Cert Guide Vol 1 from Cisco Press. There were two reasons behind my eagerness first being written by two different authors Narbik Kocharians and Peter Paluch and the second reason being the version change of the CCIE Routing and Switching exam. Thanks to Cisco Press and a Jamie Shoup for proving me the copy of the CCIE Routing and Switching v5.0 Official Cert Guide Vol 1.


The tile CCIE Routing and Switching v5.0 Official Cert Guide Vol 1 does follows typical style and format of other Cisco Press books, yet it’s quite different in many aspects. In past one volume used to cover all the topics of the CCIE Routing and Switching exam, however for version 5 Cisco Press came out with two volumes, the first volume covers topics like

  • –Virtual LANs and VLAN Trunking
  • –Spanning Tree Protocol (STP)
  • –IP services (ARP, NTP, DHCP, NAT, SNMP, NetFlow, and more)
  • –RIPv2 and RIPng
  • –EIGRP
  • –OSPF v2 and v3
  • –IS-IS
  • –Route redistribution, route summarization, default routing, and performance routing

This approach is quite good especially when the CCIE Routing and Switching exam demands more resources in depth, which the authors Narbik Kocharians and Peter Paluch have done in an excellent fashion. The OSPF chapter is the most liked chapter for me, especially the way the authors have simplified the topics is quite interesting. OSPF always remains to be the confusing and hard topic either when it comes to wither exams or a job interview. This chapter certainly helped me to understand the concepts in much more simpler fashion.

The second thing I liked about this title is the language used by the authors, it’s quite simple, easy to understand and the examples demonstrated for any topics are quite helpful.

I have been using the Advance CCIE Routing & Switching v5.0 work book developed by Narbik and it’s quite good, and did had huge expectations from Narbik Kocharians and Peter Paluch which they kept.

This title does comes with practice test as well, the good thing I noticed from Cisco Press is they included the “ Do I know this Already” questions from the title. This makes life easier for the CCIE aspirers.

When it comes to resources for the CCIE Routing and Switching exam one does needs to go thorough lot of resources, I certainly recommend this title to part of their journey of CCIE Routing and Switching exam. Once I get an opportunity I would certainly like to review the second volume.

In a nut shell a very good resource not only serves the journey of CCIE Routing and Switching exam but also serves as a reference guide for Network Engineers.

July 2, 2014  10:04 AM

CCIE Lab exams to cost more

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

Recently Cisco increased the exam costs for various certification exams. The details can be found in the below table.


Now CCIE written exam will $ 400 each whereas the lab will cost $1600 per attempt. In past the CCIE written exam was priced at $ 350 and the lab was priced at $ 1500. From now on the CCIE aspires have to ensure that they have to pay $ 2000 as test fees which does not include the travel cost. You can find the new fees at following link.

April 19, 2014  8:03 AM

INE announced their detailed CCIE Routing and Switching version 5 blue print

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

As we all aware that the last day for CCIE Routing and Switching v4 Lab exam happens to be on 3rd of June 2014. Even those who want to book the CCIE Routing and Switching v4 Lab exam before June 4, 2014 they all ran out of luck as all the seats are full. This gives us the hope to look forward for CCIE Routing and Switching v5 Lab exam which Cisco is offering from 4th of June 2014.

Those who are preparing hardly for this prestigious certification, they always keep a close eye on its development. The biggest contributor in terms of study materials and work books for CCIE certifications happens to be INE. I found their materials to be of high quality and they do produce their material to equip the INE students to understand the concepts well and always ready to face the challenge of CCIE labs.

Some of their material really helped me a lot in resolving real time problems especially in the routing and switching segment. Just two days back INE announce their detailed blue print for the CCIE Routing and Switching Version 5 exam. It’s worth to have a close look at this blue print, this blue print is certainly helping us to  come out with the detailed study plan for CCIE Routing and Switching v5 Lab exam. I am pretty sure once their Work books are out, they will guide us towards the successful journey of CCIE

March 6, 2014  10:24 AM

How does the new CCIE Routing and Switching Version 5 lab format looks like?

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

CCIE Routing and Switching lab version 4 lab format consists of two modules namely

1)      Troubleshooting

2)      Configuration

However with the announcement of CCIE Routing and Switch Version 5 we are going to see some significant changes in the lab format and how it is delivered. The new lab format consists of three modules namely

1: Troubleshooting (TS)
2: Diagnostic (DIAG)
3: Configuration (CFG)

CCIE V5 Lab1

In past only TS lab were delivered using virtual devices (IOU) however with the introduction of V5 both the CFG and TS are delivered using virtual routers ( IOL –IOS on Linux) and Virtual Switches ( L2IOL – Layer 2 IOL). These type of delivery will provides an option to reload the initial configuration for any devices much faster. Also one more difference we are going to experience is there are only Ethernet and Serial interfaces no more fast Ethernet or Giga Ethernet interfaces.

Web delivery

By adding new module Diagnostic (DIAG) Cisco is now giving the flexibility in timing for TS and CFG modules, one has the freedom to borrow 30 minutes from either TS or CFG modules, however the borrowed time maximum of 30 minutes has to be compensated, for example if one use 2hour 30 minutes for TS lab then he is entitled to get only 5 Hours 30 minutes for the CFG lab as shown below.

DIAG module works with no devices, basically it is designed to test the troubleshooting and analytical skills of CCIE exam taker. It comprises of multiple choice question including drag and drop questions and the time allotted for this module is fixed and cannot be varied. One gets a maximum of 30 minutes to answers all questions with no access to any devices.

Cisco says “A new exam module called “diagnostic module” has been added and will focus on the skills required to properly diagnose network issues. The time for this new lab module is fixed to 30 minutes, no more or no less.”

I wish all the CCIE dreamers best of luck in their exams, please do share your ideas in the comment box.

March 6, 2014  5:18 AM

Review for “Cisco CCIE Routing and Switching v5.0 Configuration Practice Labs, 3rd Edition”

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

When it comes to CCIE Routing and Switching lab exams every CCIE dreamer will certainly look at possible Lab scenarios, practice materials and work books which they practice in real Cisco Switches and Routers. It’s a known phenomenon that without appropriate practical practice for CCIE Lab it’s hard to achieve.

Cisco Press are the first one to release practice lab guide called “Cisco CCIE Routing and Switching v5.0 Configuration Practice Labs”.  This title really aims to prepare the CCIE dreamers practically in terms of configuration for the version 5 lab exam. This title comes with 3 full practice labs which covers all the layer 2 and layers 3 topics of the CCIE Routing and Switching Version 5 blueprint as shown below

CCIE topics

These practice labs ensures that the CCIE aspirer is spending 8 hours in solving each practice lab.  Which comes very handy and gives an edge as well as confidence to those who are appearing for the CCIE R & S V5 lab exam.

Each practice lab starts with the topology used along with the list of equipment’s required to setup the lab at your home. The handy thing about this title is it comes with the configuration files both the initial and final in the text format which you can use to build your own lab and can also verify your configuration with the final text file as well.

Each Practice labs addresses question seven sections with predefined points which will certainly give an overview of the progress you are making and can further strengthen the concept where you are failing, I likes this approach. One more key point I would like to highlight is “Ask the Proctor” part of this title, which provides the clarity, direction and clue to the each question asked in every section of the practice lab. This seems to be very handy especially when one finds the task quite challenging. Each practice lab ends with Debrief and Lab wrap-up. The debrief part if very helpful as it gives  you a very clear view on the points you scored for the each task and further provides you an opportunity to further strengthen the concepts which you are failing.

Over all I found the title “Cisco CCIE Routing and Switching v5.0 Configuration Practice Labs” quite handy and helpful for the preparations of Cisco CCIE R & S V5 lab exams, for which I would like to thank the author Martin James Duggan. If the Lab topologies were provided in single pages that would have been very handy and helpful for the candidates, and if Cisco Press would have provided an option of bundling the title “Cisco CCIE Routing and Switching v5.0 Configuration Practice Labs” with some real gears or Virtual labs for practice would have added more value.

March 3, 2014  3:44 AM

Cisco Press Releases Cisco CCIE Routing and Switching v5.0 Configuration Practice Labs, 3rd Edition

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

Those who are aspiring to be a Cisco CCIE Routing and Switching and are quite anxious about the version 5. Most of them are thinking how the lab will be? What kind of topology will they face in the lab? It quite too early to anticipate more details about the Cisco CCIE Routing and Switching Version 5 Lab. June 4 2014 is going to reveal more details.

Meanwhile to guide the Cisco CCIE Routing and Switching Version 5 aspirers, Cisco Press released their first series of CCIE study materials on 27th of Feb 2014.  The Cisco CCIE Routing and Switching v5.0 Configuration Practice Labs comes with three full configuration lab scenarios in the CCIE R & S V5 exam format. This will certainly give you an idea how the CCIE R & S V5 lab may be. The sample chapter really looks amazing and from that I could see its ideal to have Six Cisco Routers loaded with Cisco IOS Software Release 15.3 T Advance Enterprise and Four Cisco 3560 X Switches with IPS 15.0S IP Services.

I will certainly come out with the detail review of the Cisco CCIE Routing and Switching v5.0 Configuration Practice Labs and do let you know how this title will assist you all in achieving your dream of Cisco CCIE Routing and Switching.

Meanwhile you can buy this title online at Cisco Press store and start the journey of CCIE in practical terms.

January 27, 2014  11:22 AM

Cisco announces new CCNP Security Curriculum

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

Cisco with draws current CCNP Security curriculum by announcing the new set of Cisco CCNP Security exams namely 300-206 SENSS, 300-207 SITCS, 300-208 SISAS and 300-209 SIMOS respectively. All the previous CCNP Security exams. 642-637 SECURE v1, 642-617 FIREWALL v1.0, 642-647 VPN v1.0, 642-627 IPS v7.0 will be available to the CCNP Security aspirers till 21st April, 2014.

The newly introduced CCNP Security certification reflects the skills and responsibilities required of today’s network security engineers, who increasingly require a holistic end-to-end understanding of a complete security posture.

Cisco is offering following training courses to CCNP Security aspirer worldwide.

Course Name Exam Number
Implementing Cisco Edge Network Security Solutions (SENSS) 300-206 SENSS
Implementing Cisco Threat Control Solutions (SITCS) 300-207 SITCS
Implementing Cisco Secure Access Solutions (SISAS) 300-208 SISAS
Implementing Cisco Secure Mobility Solutions (SIMOS) 300-209 SIMOS

Following is the migration chart for those who are already in the process of CCNP Security Certification

CCNP Migration

I believe the current security evolution with the invent of Cloud, Big Data, third platform and especially the emergence of Next Generation Firewalls made Cisco rethink their strategy towards CCNP Security Certifications. Soon we can expect many titles popping out from Cisco Press for the CCNP Security preparation.

January 22, 2014  12:18 PM

Cisco announces Cybersecurity Specialist certification

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

It’s a known fact that there is a huge demand for cybersecurity experts, in fact it’s been estimated that the demand for cybersecurity experts growing at 12 times the overall job market. Cisco always wants to stay ahead in race so they came out with a new Cisco Cybersecurity Specialist certification which provides the essential skills for network security analysts who specialize in proactive network security threat detection and mitigation.

The prerequisite for the Cisco Cybersecurity Specialist certification is a Cisco CCNA Security certification.

The newly announce Cisco Cybersecurity Specialist certification exam covers the following topics

1.0   Information Gathering and Security Foundations

2.0   Event Monitoring

3.0   Security Events and Alarms

4.0   Traffic Analysis, Collection, and Correlation

5.0   Incident Response

6.0   Operational Communications

Exams & Recommended Training

Required Exam(s) Recommended Training
600-199 SCYBER Securing Cisco Networks with Threat Detection and Analysis (SCYBER)

Looks like a promising certification for the Security Professionals

January 17, 2014  10:42 AM

Are Catalyst 6800 Series Switches going to rule campus backbone like Cisco Catalyst 6500 Series switches

Yasir Irfan Yasir Irfan Profile: Yasir Irfan

Yesterday Cisco announced that they started shipping out their newly introduced Catalyst 6800 Series Switches. Currently they are shipping the Cisco Catalyst 6807-XL and 6880-X Switches. We all know when it comes to Campus backbone switches Cisco Catalyst 6500 Series Switches ruled the industry for more than decade.


I think this is the right time for Cisco to concentrate and promote the new flagship of their products especially the Campus backbone Category. The Cisco Catalyst 6800 Series Switches are programmable campus backbone switches optimized for 10/40/100 Gigabit Ethernet services. They provide slot capacity up to 880 G, and smart and simple network operations using Catalyst Instant Access. These switches offer converged wired, wireless, and VPN security, and exceptional investment protection with their Catalyst 6500 DNA

Some of the unique features of the Catalyst 6800 Series Switches are


Help ensure that the campus is ready for 10/40/100 Gigabit Ethernet services with the higher slot and switching capacity of Catalyst 6800. The 6800 Series offers the highest-density 10 Gigabit Ethernet ports that:

  • Include advanced enterprise Multiprotocol Label Switching (MPLS), Virtual Private LAN Service (VPLS), and Multicast functionality
  • Support multirate interfaces for easy migration from 1 Gigabit Ethernet to higher throughput services

Cisco Catalyst 6807-XL Switches can scale to 880 Gb per slot and 11.4-Tbps (full duplex) switching capacity. For midsize campuses, Cisco Catalyst 6880-X Switches provide scalability with eighty 10 or twenty 40 Gigabit Ethernet ports.


Built for Programmability

Catalyst 6800 switches support the Cisco One Platform Kit (onePK) software-defined networking (SDN) toolkit. You can easily build applications to automate operations and create services across the campus.

The 6800 Series Switches also support the industry-standard OpenFlow interface. You can program these switches for custom network services such as network slicing and traffic steering.

 Built for Unified Access

The Catalyst 6800 series facilitates:

Five nines (99.999 percent) availability with next-generation Cisco Virtual Switching System (VSS) technology (VSS Quad Supervisor SSO [VS4O])

  • One policy with Cisco Identity Services Engine
  • Centralized management with Cisco Prime infrastructure
  • One network with Cisco Wireless Services Module 2 (WiSM2)

The Catalyst 6800 Series Switches comes in three models

Cisco Catalyst 6880-X Switch

Cisco Catalyst 6807-XL Switch

Cisco Catalyst 6800ia Switch

I wish Catalyst 6800 family a successful journey and I am pretty sure like Cisco Catalyst 6500 Series switches it’s going to rule the Campus Backbone Category of Switches for coming decade.

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