Sorry, this entry is only available in Portugues.

Hello Guys,

The BCMSN is a complicated test to practice, because the part of the simulator always lacks something.

In my environmental studies, found that when using the Boson Netsim the Packet Tracer and I Dynamips support for almost everything. My next post will be about what each of these tools supports.

In this post I will make an overview of the functioning of the protocols and focarei a diagram showing the main points of each.

Per hour, we talk about high availability. In routers and switches from Cisco L3 are available: HSRP (Hot Standby Router Protocol), VRRP (Virtual Router Redundancy Protocol) and GLBP (Gateway Load Balancing Protocol). Below, will be a short description of how these protocols work.

The first two (HSRP and VRRP) act in ways similar. In both, each router receives an IP that is not the gateway. The routers are configured to talk to some of these protocols exchange hello messages to find out who will be elected the primary, based on higher priority (higher IP used as a tie if the priority is the same). The primary answer for your router IP and the IP set to gateway. Thus, if the router fails, when the secondary router is not given time to communicate (because the dead time) it will assume the role of primary and send its MAC address (the ARP protocol) to take notice of the IP gateway.

The GLBP was developed to support load balancing. The routers have two roles:

• A router is elected the AVG (active virtual gateway), this answer all ARP requests at the gateway. A ‘catch’ is that it responds with the MAC-address of each of the other routers, based on the algorithm of load balancing. Algorta are the Round-robin (default), weighted, and host-dependent.
• Maximum 4 routers (including AVG) AVFs are (active virtual forwarder) and participate in the process of transferring data.

Below is presented a diagram showing the main points of each of these protocols.

The book utilized in this summary was the CCNP BCMSN Official Exam Certification Guide, por David Hucaby.

A big hug,

Maurício Bento Ghem.