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dingdongboomNetworking and Communications

Oct 27, 2013 (3 years and 7 months ago)

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Autumn 2000

John Kristoff

1

Computer Networks

Other Network Protocols

Autumn 2000

John Kristoff

2

Motivation

Even though TCP/IP may have won the
protocol wars, you will be able to
understand networking and even TCP/IP
better if you learn about contrasting
solutions and implementations. This may
help you to avoid reinventing the wheel or
perhaps to borrow from the past's good
ideas to solve seemingly new problems.

Autumn 2000

John Kristoff

3

Novell IPX/SPX

Ñ
Novell proprietary

Ñ
Based on Xerox's XNS protocol system

Ñ
Runs on top of Ethernet, Token Ring, etc.

Ñ
Usually used with NetWare OS's

Ñ
Very popular in corporate environments

Ñ
Declining usage

Autumn 2000

John Kristoff

4

Novell Protocol Stack
Illustrated

Autumn 2000

John Kristoff

5

Internetwork Packet
eXchange (IPX)

Ñ
32
-
bit network, 48
-
bit node/host address

Ñ
Network is generally fixed at 32
-
bits

Ñ
Node address = IEEE 802 MAC address

Ñ
Dynamic host address assigment

Ñ
Many features IP wishes it had!

Autumn 2000

John Kristoff

6

IPX Routing

Ñ
IPX Routing Information Protocol

Ñ
TTL counts up

Ñ
NLSP

Ñ
Similar to OSPF and IS
-
IS

Ñ
Never took off

Ñ
Concept of internal IPX numbers

Autumn 2000

John Kristoff

7

Sequenced Packet
eXchange (SPX)

Ñ
Similar to TCP, but with no sliding window!

Ñ
SPX II addressed the window size problem

Ñ
Though, not really well

Ñ
Most Novell based apps avoided SPX

Ñ
It was inefficient and just got in the way

Ñ
Some newer apps used SPX II (e.g. Notes)

Autumn 2000

John Kristoff

8

Service Advertisement
Protocol (SAP)

Ñ
Services are advertised periodically

Ñ
The anti
-
DNS system

Ñ
e.g. "I'm a Netware printer, here I am!"

Ñ
Default interval was every 60 seconds

Ñ
Very chatty on large networks

Ñ
Does not scale

Ñ
NDS was supposed to help

Autumn 2000

John Kristoff

9

NetWare Core Protocol
(NCP)

Ñ
Novell's layer 5, 6 and 7 layers
-

kinda

Ñ
File access protocol

Ñ
Print services

Ñ
Login/authentication requests

Ñ
Messaging/management services

Ñ
Provided "burst mode" for file read/writes

Autumn 2000

John Kristoff

10

NetWare Directory Services
(NDS)

Ñ
Hierarchical database of network objects

Ñ
Based on X.500 and works with LDAP

Ñ
Logical and physical objects represented

Ñ
Leafs, containers, users, drive mapping, etc.

Ñ
Naming structure similar to DNS

Ñ
e.g. jdoe.networks.acme_us.

Ñ
Partitions and replicas stored on servers

Autumn 2000

John Kristoff

11

AppleTalk

Ñ
De Facto standard from Apple for Macs

Ñ
Very easy for end users

Ñ
Very chatty
-

scaling problems

Ñ
Runs on top of LocalTalk, Ethernet, Token
Ring, etc.

Ñ
TokenTalk and EtherTalk technologies
developed to support AppleTalk over IEEE
LANs

Autumn 2000

John Kristoff

12

This Picture is Wrong!

Autumn 2000

John Kristoff

13

AppleTalk Network Layer
Addressing

Ñ
Only 3 bytes for network layer addresses!

Ñ
2 bytes for network, 1 byte for host/node

Ñ
Networks can be
ranges

Ñ
e.g. 135
-
141

Ñ
Arbitrary size, unlike IP (x
2
)

Ñ
Looks/Requests network address

Ñ
Chooses host/node address at random!

Ñ
Sends an AARP and looks for a reply

Autumn 2000

John Kristoff

14

AppleTalk Routing

Ñ
Routing Table Maintenance Protocol
(RTMP)

Ñ
Similar to RIP

Ñ
Seed Router

Ñ
1 router configured with network, others learn

Ñ
Nodes can optimize best exit router by
examining received packets

Ñ
Associates NET with ROUTER ADDRESS

Autumn 2000

John Kristoff

15

AppleShare

Ñ
Centralized file sharing system

Ñ
Runs on top of AppleTalk

Ñ
Also allows for

Ñ
Printer sharing

Ñ
Peer to peer sharing

Ñ
Mail handling

Ñ
Security functions (ids and passwords)

Autumn 2000

John Kristoff

16

ISO Network Layer

Ñ
Connectionless Network Layer Protocol
(CNLP)

Ñ
Variable length, 20 bytes max

Ñ
Address specifies a host rather than an
interface

Ñ
Was considered to replace IPv4

Ñ
Provided for autoconfiguration like IPv6
and IPX

Autumn 2000

John Kristoff

17

ISO Routing

Ñ
Intermediate System to Intermediate
System (IS
-
IS)

Ñ
Link state routing protocol

Ñ
Very similar to OSPF

Ñ
Widely used by many ISPs

Ñ
Runs directly on top of a layer 2 protocol

Autumn 2000

John Kristoff

18

ISO Transport Layer

Ñ
Transport Protocol (TP)

Ñ
Four classes of transport layer protocols

Ñ
TP0, TP1, TP2, TP3, TP4

Ñ
Each provide increasing degree of features

Ñ
TP4 is similar to TCP

Ñ
Three
-
way handshake

Ñ
Sliding window

Ñ
Retransmission timer

Autumn 2000

John Kristoff

19

ISO Protocol Stack
Illustrated

Autumn 2000

John Kristoff

20

DECnet

Ñ
Most commonly referred to as Phase IV

Ñ
Earlier phases and Phase V also defined

Ñ
DECnet Phase V was CLNP or IP

Ñ
Only 2 bytes for addresses in Phase IV!

Ñ
6 bits for network (area), 10 bits for host/node

Ñ
Traditionally implemented on Digital
Equipment Corp. machines (e.g. VAX)

Ñ
Ported to many other systems

Autumn 2000

John Kristoff

21

DECnet Protocol Stack
Illustrated

Autumn 2000

John Kristoff

22

Systems Network
Architecture (SNA)

Ñ
Proprietary architecture from IBM

Ñ
There is no true layer 3 function in legacy
SNA
-

no routing!

Ñ
Historically built for token ring and source
routing (that was the layer 3 network)

Ñ
Central control (dumb terminals)

Ñ
APPN came later to provide distributed
control

Autumn 2000

John Kristoff

23

SNA Protocol Stack
Illustrated

Autumn 2000

John Kristoff

24

SNA Components

Ñ
Hosts (mainframe)

Ñ
Communications controller/FEP

Ñ
Cluster controllers
-

like a hub

Ñ
Terminals and printers

Ñ
Software (VTAM, NCP, emulation)

Ñ
Physical and logical concepts (PUs/LUs)

Autumn 2000

John Kristoff

25

Network Basic Input Output
System (NetBIOS)

Ñ
A simple API for LAN applications

Ñ
Assigns names for nodes on the network

Ñ
Very chatty
-

does not scale

Ñ
No network layer

Ñ
Often uses the NetBIOS Extended User
Interface (NetBEUI)

Ñ
Server Message Block (SMB) used to
provide file/print sharing (e.g. Samba)