Unit 12
Chapter 7
Rising Above Layer 2: Static and Dynamic Routing
Routing Tables
Windows
route print #or netstat -rn
Linux
ip route #or netstat -r #or route -n
TTL : Time to Live (IPv4)
Hop Limit (IPv6)
Default route (gateway)
Connecting Private Networks to Public Networks: NAT
NAT (network address translation) is a common function of the router at the edge of your LAN.
Routing Protocols
Static routing protocols use hand-entered routes.
Dynamic routing protocol routers update each other automatically.
How fast can routers achieve convergence?
Internal Protocols
Distance-Vector Routers
How many hops between two hosts? Choose the lowest “cost”.
RIP (v1)
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- Max hop count of 15
- Routing table updates every 30 seconds, and the WHOLE TABLE
- No VLSM (CIDR)
- No authentication
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RIP v2
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- Yes VLSM
- Authentication added
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RIPng
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- For IPv6
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EIGRP (Cisco proprietary)
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- Incremental updates
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Link-State Routers
Which routes use the fastest links? Which routes are currently up? Choose the fastest.
OSPF
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- Noisy boot HELO packets
- Then LSAs to converge
- Metric is COST not HOPS
- Authentication
- Prevents loops
- Detect and corrects link errors/failurs
- Converges immediately
- v3 supports IPv6
- Area 0 is the backbone (or only) layer, to divide routers into smaller areas for fast convergence and small routing tables
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IS-IS
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- IPv6 Native from its creation
- ISP standard router
- Multi-pathing!!!!!
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Exterior Protocols
BGP
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- Also hybrid
- Ties ASs together
- https://en.wikipedia.org/wiki/Border_Gateway_Protocol
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Coming Over the Horizon
MTCP : Multipath TCP
“Exotic” or Large-Scale Network Protocols
MPLS – https://duckduckgo.com/?q=mpls&t=ffab&iax=images&ia=images