Cisco OpFlex

Cisco ACI uses OpFlex to communicate with VMWare DVS/VDS. OpFlex is an extensible policy protocol designed to exchange abstract policy between a network controller and a set of smart devices capable of rendering policy. OpFlex relies on a separate information model understood by agents in both the controller and the devices. This information model, which …

RIPv2 Notes

RFC 2453 - RIP Version 2 Distance Vector IGP. Routers only know what directly connected neighbours tell them (Routing by Rumour). Routers only know what is the routing as it told by neighbours but does not actually know the state/condition of the route itself. Only RIP routes installed in RIB are advertised. Distance Vector routing …

RIP Offset-List

Two routers R9 and R7 where R7 is connected to the rest of the network and R9 is the edge network. All of the network is exchanging routes via RIP version 2 with no-summary option. R7 has 155.1.5.0/24 with metric of 2 received from the network and advertise this 155.1.5.0/24 to R9 via its G0/1.79 …

Storm-Control

Storm Control blocks an interface upon receiving unicast, multicast, or broadcast packets flood based on the threshold value within one second period of time. This can be handy to prevent or at least reduce network flooding activities that can impact the network performance. When the offending traffic reaches the Rising Threshold (RT), the interface blocks …

Visio Flat Network Icon

I have created just a few standard Microsoft Visio Flat Network icons and they are available for all to use and share. The idea was to have network icons that are 2D instead of the 3D version for drawing consistency and making it easier to apply Visio diagram theme. These icons allow you to un-group …

MST Notes

History Spanning Tree Protocol (STP) is a protocol to ensure there is no loop in layer 2 network. This protocol was invented by Radia Perlman in 1985 and published as a standard originally as IEEE 802.1D-1990. In essence, STP works by sending a probe to every layer 2 switches and decides which link should be …

IGMPv2 – RFC 2236

While PIM controls the communication between multicast routers, IGMP is the control protocol between routers and hosts. IGMP is similar with ICMP and it has IP protocol number 2. Because the intention is the communcation between hosts and routers, it is only sent as a link-local packet that has TTL of 1 in the IP …

PIM Sparse-Mode (SM) Notes – RFC 4601

Uses both Shared-Tree (*,G) and Source-Tree (S,G). PIM Sparse-Mode (SM) steps: Discover PIM neighbor and elect DR. PIM is the infrastructure to deliver the multicast packet. It builds the multicast network hop-by-hop. It takes the advantage of the routing table to perform RPF but it does not really matter what routing protocol derives it from. …

InternetworkExpert updates its CCIE R&S Material

I'm actually countering my dissapointment to INE with good product updates they recently released. First of all, I'm studying for CCIE R&S v4.0. Therefore, I need to have materials that specifically design for v4.0. Looking to the WB1 I have from INE, I was quite surprised to know that INE updated the WB with additional …

Heaps of Omnigraffle Stencils

I used Omnigraffle about a year ago then I remember I had difficulties to draw network diagram based on Cisco Stencil. I posted Cisco Stencils for Omnigraffle and that was pretty much the only available Cisco Stencil during that time. I'm reopening my Omnigraffle 'cause I'm quite lazy to switch to other laptop and start …