BGP Route Reflector Basics

Everyone who ever studied BGP knows that BGP has strong rules to prevent routing and updates loops. In this post I will focus on iBGP loop prevention and specifically route reflectors as a result. The rule states: that any route received from an iBGP neighbor must not be advertised to any other iBGP neighbor. This loop prevention mechanism induces a requirement that all iBGP routers in the network should be connected in logical full mesh topology to allow for routing information propagation through out the network. However, full mesh connectivity has never been a scalable solution specially in large networks. Two mechanisms …

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Interview with Emmanuel Conde

Today I have a special treat for you — an exclusive written interview with the CCIE Agent Emmanuel Conde. Eman (Emmanuel Conde) has the distinction of being the only CCIE recruiter promoted by World Wide Channels of Cisco Systems.   Eman earned this distinction because of his tireless efforts on behalf of CCIEs and developing Cisco talent.  He has spoken at Cisco Academy events, developed an international CCIE mentor program, writes for ITWorld magazine, has a very active blog focused on CCIE career concerns, and produces the CCIE Flyer an online magazine published monthly.  He has developed a unique approach to …

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ARP Caching and Timeout

From time to time I find myself craving to the fundamentals; I do this for two main reasons, the first one is that fundamentals are the building blocks of all complex networking topics and deeply understanding them makes a better engineer, the second one is longing to simplicity after doing some complex tasks. One of these fundamentals that is worth reviewing is the Address Resolution Protocol, this protocol is one of the main building blocks of any network existing on earth today.

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MPLS VPN security threats

MPLS L3 VPN services is widely used nowadays by many enterprises and organizations. They provide a lot of flexibility in connecting different sites compared to L2VPN services and offloads a lot of the responsibilities from the enterprise to the provider. I have gained all my networking experience in service provider environments, and have seen very little number of customers taking VPN security seriously. While  for most of them security is a very critical issue to consider. Banks, Travel agencies and stock brokerages have very critical applications that require a high level of security planning.

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Static routes and next hops

Today I have received a question by mail from one of our readers asking about the difference between pointing the static route to a next hop address or pointing it to the exit interface itself as shown in the example below: !-- Pointing to next hop address ip route 0.0.0.0 0.0.0.0 192.168.1.1 !-- or Pointing to the interface ip route 0.0.0.0 0.0.0.0 s1/0 Although it seems to be an easy question to answer but I it was a little bit hard for me to write the answer in words. You know, sometimes we know things but when time comes for …

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LDP neighbor discovery, session establishment and maintenance

Team working is all about producing results with a group of people you love working with … Being part of the same team, working together all day long we decided to extend this level of team working from being members of the same team and writing in the same blog to even write this post together. In this post we are transferring our daily team work interaction from our office to the blog. The case was simply manipulating the LDP timers at a node suffering from connectivity issues. To be able to master this arena you need to perfectly understand …

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