Network Topology JOHNNY JACOBS Networks as Graphs Simplified - - PowerPoint PPT Presentation

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Aug 14, 2023 130 likes •355 views

Network Topology JOHNNY JACOBS Networks as Graphs Simplified abstraction Intuitive Nodes are hosts, routers, switches Edges are connections Allows simulation Convenient Cost effective What is Topology? Generally

SLIDE 1

Network Topology

JOHNNY JACOBS

SLIDE 2

Networks as Graphs

 Simplified abstraction  Intuitive

 Nodes are hosts, routers, switches  Edges are connections

 Allows simulation  Convenient  Cost effective

SLIDE 3

What is Topology?

 Generally

 Branch of mathematics concerned with geometric

relation between points

 Computer Networks

 Physical topology

 Physical connections

 Logical (Network) topology

 Data flow

SLIDE 4

How is it useful?

 Network Management

 Reliability

 Identify points of failure

 Routing  Throughput  Root cause analysis

 Topology dependent algorithms

 Cycles

 Other insights

SLIDE 5

Base Protocols

 Broadcast Protocols

STP(Spanning Tree Protocol)

 Routing Protocols

RIP(Routing Information Protocol) OSPF(Open Shortest Path First)

 Management Protocols

SNMP(Simple Network Management Protocol) ICMP(Internet Control Message Protocol)

SLIDE 6

Broadcast Protocols

SLIDE 7

STP

SLIDE 8

STP

 Builds a spanning tree

 All nodes connected  Not redundant edges  Not necessarily minimal

 Allows for efficient broadcast

SLIDE 9

Internet Routing Protocols

SLIDE 10

RIP

SLIDE 11

RIP

Essentially distance vector Uses hop count (limit 15)

Every link has cost 1

Share up to 25 destinations Share on change Share every 30 secs

Neighbor dead if not heard in 180 sec

SLIDE 12

OSPF

SLIDE 13

OSPF

 Hierarchical

 Dijkstra's  Broadcast link state  Configurable link weight metric

Ex. Hops, inverse capacity, etc.

Authentication

 Multi-path  Hello messages

SLIDE 14

Network Management Protocols

SLIDE 15

SNMP

SLIDE 16

SNMP

 Single manager, many agents

 Agents can be anything: routers,

hosts, switches

 Operates mostly on MIB

(management information base)

 information store, holds state of

network

 Mostly requests for, or setting of,

MIB

SLIDE 17

ICMP

SLIDE 18

ICMP

Top-level diagnostic messages Ping requests/replies Traceroute

TTL expiration and destination unreachable

SLIDE 19

Putting it together

SLIDE 20

Hybrid Algorithm

Network Topology

 Uses routing tables from SNMP MIB information to identify

routers and switches Physical Topology

 Probes subnets using OSPF and STP

SLIDE 21

Bibliography

 Textbook and slides  http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=6414020  Title image: commons.wikimedia.org  Other images:

 http://www.electricmonk.org.uk  http://www.bogotobogo.com