BGP

This class provides a top down, practical exposure to the Border Gateway Protocol. Students will walk away from this class confident and comfort with BGP engineering. Whether they have prior exposure to BGP or not, this class will solidify the foundational BGP concepts pave the way for a student’s eventual mastery of the protocol.

Target Audience

Network Engineers who need a practical run-down on configuring and troubleshooting BGP on Cisco routers.

Pre-requisites

Each student will need access to nine Cisco routers, real or virtual. If needed, Practical Networking can provide access to virtual Routers for an additional fee.

Syllabus

This class is broken up into three parts.

BGP I focuses on the essential BGP knowledge. Starting with the preliminary knowledge required to understand BGP’s role in Internet engineering, then going immediately into the practical skills needed to start configuring BGP: Configuring BGP peers and advertising routes into BGP.

BGP II concentrates on the BGP Path Selection process. The class first defines the different attributes that exist within BGP to influence path selection. The course then transitions into a progressive lab where each step of the Path Selection process is explained and then immediately proved in a lab. By the end of this class, the student will know every step in the path selection algorithm and how to tweak each attribute to granularly control the path for incoming and outgoing traffic.

BGP III focuses on advanced BGP concepts like Multi-Protocol BGP (MP-BGP), MPLS, and VRFs. Specifically how each of these three technologies come together to provide a plethora of WAN connectivity options that fall into two categories: L2VPNs and L3VPNs. As with BGP II, the intersection of each of these technologies is brought together through various labs giving the students practical, hands on exposure to working with these technologies.

Modules:

BGP I

• BGP Essentials
  • Overview
  • Autonomous Systems
  • Loop Prevention
  • Demonstration
• BGP Peering
  • Peering
  • Messages
  • Neighbor States
  • Parameters
    • Router-ID
    • Hold Time
    • Update-Source
    • TTL
  • Verification
    • show ip bgp summary
    • show ip bgp neighbors
  • Advertising Prefixes
    • Advertising
      • Network command
      • Redistribution
    • Verification
      • show ip bgp
    • Route-Maps
      • Syntax
      • Access-lists
      • Prefix-Lists
      • AS-Path access-lists
    • Aggregation
      • Network command
      • Aggregate-address command
        • Suppress-map
        • Summary-only
        • As-set
      • Re-Advertising
        • Transit black hole
        • iBGP full mesh
        • Route-Reflector

BGP Day II – Path Selection

• Path Attributes
  • Path Attributes
  • Well-Known Attributes
    • AS-Path
    • Next-Hop
    • Origin
    • Local-Preference
    • Atomic Aggregate
  • Optional Attributes
    • Aggregator
    • Communities
    • Multi-Exit Discriminator (MED)
    • Weight
  • BGP Tables
    • Adj-RIB-IN
    • Local-RIB
    • Adj-RIB-out
    • Route Refresh
    • Soft-reconfiguration inbound
• Path Selection
  • If next-hop is inaccessible, drop the update
  • Prefer path with the largest Weight
  • Prefer path with the largest Local-Preference
  • Prefer path with locally originated routes vs externally learned
  • Prefer path with shortest AS-Path
  • Prefer path with best Origin (IGP > EGP > Incomplete)
  • Prefer path with lowest MED
  • Prefer path learned from eBGP over iBGP
  • Prefer path with the lowest IGP metric to the next-hop IP
  • Prefer path with the greatest age (oldest path – eBGP only)
  • Prefer path learned from neighbor with lowest Router ID
  • Prefer path learned from neighbor with lowest Neighbor IP Address

BGP III

• Supporting Concepts
  • MPLS
  • MP-BGP
  • VRF
• L3VPN
  • Route Distinguishers
  • Route Targets
  • MP-BGP VPNv4
  • MP-BGP VRF
• L2VPN
  • Pseudowire