Transcript Other Network Protocols

Computer Networks
Other Network Protocols
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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.
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Novell IPX/SPX
Novell proprietary
Based on Xerox's XNS protocol system
Runs on top of Ethernet, Token Ring, etc.
Usually used with NetWare OS's
Very popular in corporate environments
Declining usage
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Novell Protocol Stack Illustrated
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Internetwork Packet eXchange
(IPX)
32-bit network, 48-bit node/host address
Network is generally fixed at 32-bits
Node address = IEEE 802 MAC address
Dynamic host address assigment
Many features IP wishes it had!
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IPX Routing
IPX Routing Information Protocol
TTL counts up
NLSP
Similar to OSPF and IS-IS
Never took off
Concept of internal IPX numbers
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Sequenced Packet eXchange
(SPX)
Similar to TCP, but with no sliding window!
SPX II addressed the window size problem
Though, not really well
Most Novell based apps avoided SPX
It was inefficient and just got in the way
Some newer apps used SPX II (e.g. Notes)
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Service Advertisement Protocol
(SAP)
Services are advertised periodically
The anti-DNS system
e.g. "I'm a Netware printer, here I am!"
Default interval was every 60 seconds
Very chatty on large networks
Does not scale
NDS was supposed to help
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NetWare Core Protocol (NCP)
Novell's layer 5, 6 and 7 layers - kinda
File access protocol
Print services
Login/authentication requests
Messaging/management services
Provided "burst mode" for file read/writes
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NetWare Directory Services
(NDS)
Hierarchical database of network objects
Based on X.500 and works with LDAP
Logical and physical objects represented
Leafs, containers, users, drive mapping, etc.
Naming structure similar to DNS
e.g. jdoe.networks.acme_us.
Partitions and replicas stored on servers
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AppleTalk
De Facto standard from Apple for Macs
Very easy for end users
Very chatty - scaling problems
Runs on top of LocalTalk, Ethernet, Token
Ring, etc.
TokenTalk and EtherTalk technologies
developed to support AppleTalk over IEEE
LANs
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This Picture is Wrong!
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AppleTalk Network Layer
Addressing
Only 3 bytes for network layer addresses!
2 bytes for network, 1 byte for host/node
Networks can be ranges
e.g. 135-141
Arbitrary size, unlike IP (x2)
Looks/Requests network address
Chooses host/node address at random!
Sends an AARP and looks for a reply
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AppleTalk Routing
Routing Table Maintenance Protocol (RTMP)
Similar to RIP
Seed Router
1 router configured with network, others learn
Nodes can optimize best exit router by
examining received packets
Associates NET with ROUTER ADDRESS
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AppleShare
Centralized file sharing system
Runs on top of AppleTalk
Also allows for
Printer sharing
Peer to peer sharing
Mail handling
Security functions (ids and passwords)
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ISO Network Layer
Connectionless Network Layer Protocol
(CNLP)
Variable length, 20 bytes max
Address specifies a host rather than an
interface
Was considered to replace IPv4
Provided for autoconfiguration like IPv6 and
IPX
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ISO Routing
Intermediate System to Intermediate System
(IS-IS)
Link state routing protocol
Very similar to OSPF
Widely used by many ISPs
Runs directly on top of a layer 2 protocol
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ISO Transport Layer
Transport Protocol (TP)
Four classes of transport layer protocols
TP0, TP1, TP2, TP3, TP4
Each provide increasing degree of features
TP4 is similar to TCP
Three-way handshake
Sliding window
Retransmission timer
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ISO Protocol Stack Illustrated
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DECnet
Most commonly referred to as Phase IV
Earlier phases and Phase V also defined
DECnet Phase V was CLNP or IP
Only 2 bytes for addresses in Phase IV!
6 bits for network (area), 10 bits for host/node
Traditionally implemented on Digital
Equipment Corp. machines (e.g. VAX)
Ported to many other systems
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DECnet Protocol Stack Illustrated
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Systems Network Architecture
(SNA)
Proprietary architecture from IBM
There is no true layer 3 function in legacy
SNA - no routing!
Historically built for token ring and source
routing (that was the layer 3 network)
Central control (dumb terminals)
APPN came later to provide distributed
control
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SNA Protocol Stack Illustrated
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SNA Components
Hosts (mainframe)
Communications controller/FEP
Cluster controllers - like a hub
Terminals and printers
Software (VTAM, NCP, emulation)
Physical and logical concepts (PUs/LUs)
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Network Basic Input Output
System (NetBIOS)
A simple API for LAN applications
Assigns names for nodes on the network
Very chatty - does not scale
No network layer
Often uses the NetBIOS Extended User
Interface (NetBEUI)
Server Message Block (SMB) used to provide
file/print sharing (e.g. Samba)
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