CCIE RS Lab – Week 4

Hours studying – 27.5

I continued working on foundations 3. This shed light on how much I need to practice more IPv6. The redistribution was nasty, there are a bunch of loops created when doing this. I used tags for the redistribution, there were no restrictions on what tech could or could not be used.

I used debug ip routing to find out if these was any loops, also check routing table and used traceroute to verify conenctivty

I did run into an issue where a route on R7 should have been learned via EIGRP from it’s directly connected neighbor, but was being learned from R6 via OSPFv3. After tracking the problem down to R6 and seeing how the route was being learned I added an deny statement on one of my route maps which restored connectvity on R7 and for the rest of the network to learn routes properly via R7’s EIGRP neighbors.

I was looking for a way to listen to videos and have them autoplay the next video. I found a way to listen to videos in the background which has helped greatly while commuting. The app on the iPhone is called PlayerXtreme, it is able to see existing videos on the phone and play them while giving additional options for play next video and increase the playback speed.

Being able to listen to the videos has increased the amount of time I’ve been able to spend “studying”. I count listening as study time as I’ll absorb some knowledge.

I have also started reading through Narbiks book, Bridging the Gap between CCNP and CCIE. So far it has been helpful and steps through the technology is a very step by step way.

I started Foundations 2 and did not run into many things I didn’t remember. I have been taking my time on this one and will be continuing it Week 5.

I was able to spend 7.5 hours on Troubleshooting Lab 1 with 2 study partners. This was the most helpful study session I’ve had in a long time. I’ll do a youtube video soon around the need for a study partner(s). We were able to discuss strategy and teach each other things we may have forgotten. This lab exposed a lot of weaknesses that I need to brush up on: OSPF LFA, BGP Table Map, Multicast MSDP, EEM tricks, BGP additional paths.

CCIE RS Lab Studying – week 1

This marks the first week of getting back into studying for the lab. I started this by getting my server running and software update. I’ve made a simple schedule, which I am already modifying and reached out to a mentor to help bounce ideas off of. On top of that I’ve got the videos loaded on my phone and iPad and added some more books to reach through safari.

For those interested. I using INE that I purchased back in the day and will continue using their material. I am also looking into Cisco360 based off feedback I’ve heard from others.

I didn’t make as much progress as I was hoping, but I’ve made a start.

So far I’ve tackled some of the L2 things just to get used to typing quickly and also going through the verifications. I’m also diving into OSPF and playing with the different network types and reading through the database.

CCIE RS – Tunneling – MPLS

Implement and Troubleshoot MPLS Operations

Multi-Protocol Label Switching

Requires CEF to be enabled on all devices running MPLS

  • Mpls ip
  • Mpls label-distribution [ldp, tdp, both]

Packet forwarding based on labels to make forwarding decisions

  • Label is 4 bytes, fixed length
    • Label – 20bits
    • Exp – 3 bits, COS
    • S – Bottom Stack, 1 bit
    • TTL – 8 bits
  • Locally significant ID
  • Forwarding Equivalence Class (FEC)
    • Group of IP packets which are forwarded in the same manner
  • Label is imposed between layer 2 (data link) header and layer 3 (network) header

Tag Distribution Protocol (TDP)

  • Cisco proprietary

Label Stack, LSR, LSP

LSR – Label Switch Router

  • Any router or switch that implements label distribution
  • Forward packets based on labels
  • Edge-LSR
    • Performs label imposition (push)
      • Prepending a label or stack of labels to a packet in the ingress point of the MPLS domain
    • Performs label disposition (pop)
      • Removing last label from a packet at the egress point before sending to neighbor outside the MPLS domain
  • Maintains a LIB table (Label Information Base)
    • Holds label mappings assigned by the LSR and mappings of these labels to labels received by neighbors
  • LFIB – Label Forwarding Information Base
    • MPLS forwarding tabel
    • Built from the LIB

LSP – Label Switched Path

  • Packets entering and exiting an MPLS network
  • Describes the set of LSR’s a labeled packet must traverse to reach the egress-LSR for a particular FEC
  • Unidirectional
  • Connection oriented scheme
    • Setup prior to any traffic flow
    • Based on topology information

FEC – Forwarding Equivalence Class

  • Grouping IP packets that are forwarded in the same manner over the same path with the same forwarding treatment
  • Might correspond to a destination IP subnet
  • After LIB is built – Labels get assigned to every FEC known by the router

Penultimate Hop Popping (PHP)

Label Stack

  • Inserted between L2 header and L3 contents of L2 frame
  • Shim header
  • 20 bits label
  • 3 bit COS / Experimental bit
  • 8 bit TTL
  • 1 bit bottom-of-stack
    • Combines 2 or more label headers attached to a single packet
  • Frame mode MPLS Actions
    • Pop – Remote top label
    • Swap – Replace top label with another value
    • Push – Replace top label with a set of labels
    • Aggregate – Remove top label and does L3 lookup of underlying IP packet
    • Untag – Remote top label and forward the underlying IP packet to next hop

 


LDP

Label Distribution Protocol

IETF Standard

Enables LSR to inform other LSR’s about label bindings that have been made.

Dynamically assign labels on a hop by hop basis

https://www.cisco.com/c/en/us/td/docs/ios/12_0s/feature/guide/fsldp22.html#wp1517250


MPLS Ping, MPLS Traceroute

mtrace


Implement and Troubleshoot Basic MPLS L3VPN

L3VPN

CE – Customer Equipment

  • Located on customer site
  • Exchanges routes with PE device

PE – Provider Edge

  • Exchanged routes with CE and other PE devices
  • Connect to both CE and P devices
  • Is part of the MPLS domain
  • Exchanges labels

P – Provider

  • Inside the MPLS cloud
  • Exchanges labels with P and PE devices
  • Does not need to know about CE routes

 

Extranet (route leaking)

Routes can be leaked between different VRF’s (customers) by using different route target import and exports.

Service providers can utilize this to help provide Internet or some other shared service connectivity from within their MPLS cloud

ip vrf VRF
rd 10:10
route-target export 100:100
route-target import 200:200
router-target import 100:100