Configuration Tips

  Before I explain what and how explicit tracking of group membership works in IGMP, let me give you a brief introduction to IGMP. A brief introduction to IGMP: Internet Group Management Protocol ( IGMP ) is used by end hosts and routers to exchange multicast group membership information. IGMP …

Protocol Independent Multicast (PIM) – Sparse mode (PIM-SM) is a multicast routing protocol. PIM-SM is used when receivers are sparsely populated. PIM-SM uses explicit-join mechanism. PIM-SM can work on point-to-point link and ethernet LANs.   Why PIM Assert mechanism is required: We will use the network configuration shown in figure-1 …

For anyone who has ever needed to test a new network architecture, implement a new routing protocol or simply study for a Cisco exam has needed access to a real live router or a router simulator.  But buying a bunch of routers just test up an idea or for study …

When configuring high availability gateways between multiple routers you only have a couple of options to choose from. If you have all Cisco routers chances are you will be configuring and using HSRP to provide redundancy between your routers. If you have Juniper, Foundry (Brocade), or any another router you’ll …

Have you heard someone using a phrase ‘Can you ping me at 8:00 PM’ or ‘Please ping me when you are free’? I am sure you must have heard people using such phrases in their daily talks. I think its fairly obvious that they want the other person to check …

Applications/Servers use IP multicast to send their contents in IP packets to a group of interested clients. These clients indicate their wish to receive such traffic explicitly by sending an IGMP (Internet Group Management Protocol) join message. In early years of IP multicast deployment, receivers and senders did not know …

TTL (Time-To-Live) is a field in the IPv4 header. TTL field is of 8 bits and so it can take a maximum value of 255. When a sender sends out a packet, it sets the TTL value (usually as 64) in the IP header. Each router that receives this packet, …

You just need to step outside to realize how much mobile phones have changed our lives. People have this need to stay connected all the time and new, faster, better performing mobiles are constantly being released. As a consequence we need to increase what we are able to do with …

As part of securing a network, access to your devices needs to be restricted and monitored. This includes direct access to routers, switches and servers but it can extend to allowing users to log on to particular services such as logging on to your ISP. It would be a tedious task if, for example, on …

As a security consultant, in the last years I’ve been involved in a good amount of projects about network firewall migration. As technology evolves and performance increases, it is normal to decide not only for a hardware upgrade but for a complete migration to a different vendor that is a …