INEv5 – VIRL Topology – Lan Switching Spanning Tree Initial

I have been using INE (Internetwork Expert) CCIE RS rack rental but sometimes I find it a bit too slow for telnet response. So, with the advent of Cisco VIRL I have created the similar lab topology so I can lab the workbooks with fast response.

Initial configuration is saved in the .virl file but it is also available in a separate file just in case VIRL does not load the full config (in this case VLANs).

Topology diagram is also available with the conversion from INE lab to VIRL lab.
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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 and make changes to suit your need. The connectors are also created around the icon to allow attaching a line.

I created these icons on Visio 2013 but I’m not sure the compatibility with the earlier version so I’ve made these available in Visio 2013 (.vssx) and earlier Visio format (.vss).
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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 block if there is a loop.

Initially STP was used with one instance. This is when there was no understanding of VLAN which was introduced later in IEEE 802.1Q. Mono Spanning Tree runs a single Spanning Tree for all VLANs. Since it uses one Spanning Tree instance for all VLANs, it lacks the ability to engineer one path over another. All VLANs will have to share the same path and fate.
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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 packet header.

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PIM Sparse-Mode (SM) Notes – RFC 4601

Uses both Shared-Tree (*,G) and Source-Tree (S,G).

PIM Sparse-Mode (SM) steps:

  1. 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. Hence this is why it is called Protocol Independent Multicast (PIM).
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Cisco IOS IPS

If you’re tasked to configure an Internet router, what features/services you would usually put in? You most definitely require NAT for LAN to Internet IP address translation, ACL for blocking unnecessary traffics from Internet to LAN, and might be a bit of router hardening by locking down some unnecessary services and management/control plane.
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