RIP

General RIP UDP-520 2 message types; - Request Message (used to ask neighbours to send updates) Response Message (Carries an update) Metric is hop-count On startup RIP broadcasts a request message packet out each RIP enabled interface - The RIP process then enters a loop - Listening for RIP requests…

Frame Relay

Frame relay is; High Performance WAN protocol Layer 2 Originally designed for use in ISDN links but now for a variety of others Packet Switched Types of Frame Relay Point-to-point; L2-L3 mapping not required as only one DLCI is allowed on P2P interface Broadcast capability is automatically enabled interface serial0/…

MPLS Configuration

Mandatory Enable CEF switching Configure LDP on every label-enabled interface Optional Configure MPLS ID Configure MTU size for labelled packets Configure IP TTL propagation Configure conditional label advertising Config mpls ldp router-id interface [force] router(config-if)# mpls ip router(config-if)#mpls label protocol [tdp|ldp|both]   #!IOS v12.4(3)…

PHP (Penultimate Hop Popping)

A label is removed on the router before the last hop within an MPLS domain. PHP optimises MPLS performance (one less LFIB lookup) PHP does not work on ATM (Virtual Path Identifiers/virtual channel identifies cannot be removed) The pop or implicit null label uses a reserved value when being…

MPLS (Multi-Protocol Label Switching)

OK, so having known about MPLS for a few years and actually get a provided service in my work environment as well as the fact it is on the CCIE R&S blueprint I thought I should get a much better understanding of how it works and the various…

UDLD

Unidirectional Link Detection (UDLD) is a Cisco proprietary extension that lives to detect miss-configured and broken links between Cisco switches. It verifies that they can both send and receive data on a point-to-point link. This can be used to assist spanning-tree and compliments things like ‘loop guard’ and ‘bridge assurance’…

Loop Guard

To prevent loops that might develop if a port that should be blocking transitions to the forwarding state we have loop guard. This could happen if a port stops receiving BPDUs, maybe due to a unidirectional (on point-to-point) link or software/configuration problem on the neighbour. The following shows an…

CCIE R&S Lab Equipment and IOS Version

I guess a key part to studying for CCIE is to understand what devices and IOS versions you will be tested on in the lab. Thanks to Cisco they let you know this information; Version 4 makes use of; 1841 series routers – IOS 12.4(T) – Advanced Enterprise Services 3825…

CCIE R&S v4.0 Blueprint

The CCIE Routing & Switching blueprint can be see below, the topics that I have covered as part of my study will have hyper-links off to the corresponding post.  This is very much work in progress so therefore is far from complete. [table id=4 /]…