Interconnections : Bridges, Routers, Switches, and Internetworking Protocols

by Perlman, Radia

• ISBN13: 9780201634488
• ISBN10: 0201634481
• Edition: 2nd
• Format: Hardcover
• Copyright: 1999-09-14
• Publisher: Addison-Wesley Professional

Summary

Offers an expert's insight into how and why networks operate as they do. Describes all of the major networking algorithms and protocols in use today in clear and concise terms, while exploring the engineering trade-offs that the different approaches represent. DLC: Routers (Computer networks).

Author Biography

Radia Perlman's work has had a profound impact on the field of networking. She was recently featured in the 25th anniversary edition of Data Communications magazine as one of the 25 people whose work has most influenced the industry. She is the creator of the spanning tree algorithm upon which bridges (switches) are based, and the algorithms that allow robust and efficient link state routing, upon which all modern link state routing protocols (such as IS-IS, OSPF, and PNNI) are based. Radia designed IS-IS, Simple Multicast, and sabotage-proof routing. She is also co-author of Network Security: Private Communication in a Public World. Both of her books were listed in the top 10 most useful networking reference books in the March, 1988 issue of Network Magazine. She is currently a Distinguished Engineer at Sun Microsystems, Inc. She holds about 50 patents and a Ph.D. from M.I.T.

0201634481AB04062001

Table of Contents

Preface	xi
Roadmap to the Book	xii
Acknowledgments	xii
Essential Networking Concepts	1	(18)
Layers	1	(6)
Service Models	7	(2)
Important Properties of a Network	9	(3)
Reliable Data Transfer Protocols	12	(7)
Data Link Layer Issues	19	(26)
Generic LANs	19	(3)
IEEE 802 LANs	22	(1)
Names, Addresses, Routes	23	(2)
LAN Addresses	25	(2)
Multicast versus Unicast Addresses	27	(1)
The Broadcast Address	28	(1)
Multiplexing Field	29	(3)
Bit Order	32	(2)
Logical Link Control	34	(1)
Issues in 802.3	35	(3)
Issues in 802.5	38	(2)
Packet Bursts	40	(1)
Reasons for Bridges	40	(1)
Point-to-Point Links	41	(4)
Transparent Bridges	45	(50)
The No-Frills Bridge	45	(2)
The Learning Bridge	47	(11)
Spanning Tree Algorithm	58	(5)
Spanning Tree Algorithm Refinements	63	(14)
Bridge Message Formats	77	(2)
Other Bridge Issues	79	(8)
Remote Bridges	87	(8)
Source Routing Bridges	95	(32)
Pure Source Routing	96	(8)
SR-TB Bridges	104	(4)
SRT Bridges	108	(1)
End-system Algorithms	109	(7)
Source Routing versus Transparent Bridging	116	(3)
Ideas for Improving Source Route Bridging	119	(8)
Hubs, Switches, Virtual LANs, and Fast Ethernet	127	(18)
Hubs	127	(5)
Faster LANs	132	(2)
Virtual LANs (VLANs)	134	(11)
Network Interface: Service Models	145	(8)
What Is the Network Layer?	145	(1)
Network Service Types	146	(7)
Connection-oriented Nets: X.25 and ATM	153	(26)
Generic Connection-oriented Network	153	(2)
X.25: Reliable Connection-oriented Service	155	(12)
Implementing X.25 Inside the Net	167	(1)
Asynchronous Transfer Mode	168	(11)
Generic Connectionless Service	179	(10)
Data Transfer	179	(1)
Addresses	180	(1)
Hop Count	180	(1)
Service Class Information	181	(2)
Network Feedback	183	(1)
Fragmentation and Reassembly	183	(2)
Maximum Packet Size Discovery	185	(4)
Network Layer Addresses	189	(32)
Hierarchical Addresses with Fixed Boundaries	190	(2)
Hierarchical Addresses with Flexible Boundaries	192	(1)
Owning versus Renting Addresses	193	(1)
Types of Addresses	194	(1)
IP	194	(5)
IPX	199	(4)
IPX+	203	(1)
IPv6	204	(7)
CLNP Network Layer Addresses	211	(4)
AppleTalk Network Layer Addresses	215	(1)
DECnet Phases III and IV	216	(2)
NAT/NAPT	218	(3)
Connectionless Data Packet Formats	221	(44)
Pieces of a Connectionless Network Layer	221	(1)
Data Packets	222	(1)
Summary of Packet Formats for Easy Reference	222	(8)
Technical Issues and Comparisons in Data Packet Formats	230	(20)
Source Routing	250	(3)
The Great IPX Frame Format Mystery	253	(3)
Error Reports and Other Network Feedback to the Endnode	256	(9)
Neighbor Greeting and Autoconfiguration	265	(34)
Endnodes Attached via Point-to-Point Links	266	(1)
Endnodes Attached via LANs	267	(17)
Endnodes Attached via Nonbroadcast Multiaccess Media	284	(9)
Finding Things	293	(6)
Routing Algorithm Concepts	299	(48)
Distance Vector Routing	299	(8)
Link State Routing	307	(13)
Comparison of Link State and Distance Vector Routing	320	(5)
Load Splitting	325	(1)
Link Costs	326	(2)
Migrating Routing Algorithms	328	(3)
LANs	331	(3)
Types of Service	334	(7)
Partition Repair: Level I Subnetwork Partition	341	(6)
Fast Packet Forwarding	347	(20)
Using an Additional Header	347	(1)
Address Prefix Matching	348	(2)
Longest Prefix Match with Trie	350	(11)
Binary Search	361	(6)
Specific Routing Protocols	367	(82)
A Brief History of Intradomain Routing Protocols	367	(2)
RIP	369	(3)
RTMP, IPX-RIP, and DECnet	372	(1)
IS-IS, OSPF, NLSP, and PNNI	373	(52)
Interdomain Routing Protocols	425	(24)
WAN Multicast	449	(30)
Introduction	449	(4)
Multicast in IP	453	(26)
Sabotage-proof Routing	479	(14)
The Problem	480	(1)
All You Need to Know about Cryptography	480	(2)
Overview of the Approach	482	(2)
Detailed Description of the Approach	484	(7)
Summary	491	(1)
For Further Reading	491	(2)
To Route, Bridge, or Switch: Is That the Question?	493	(10)
Switches	493	(1)
Bridges versus Routers	493	(3)
Extensions to Bridges	496	(2)
Extensions to Routers	498	(5)
Protocol Design Folklore	503	(20)
Simplicity versus Flexibility versus Optimality	503	(2)
Knowing the Problem You're Trying to Solve	505	(1)
Overhead and Scaling	506	(1)
Operation Above Capacity	506	(1)
Compact IDs versus Object Identifiers	507	(1)
Optimizing for the Most Common or Important Case	507	(1)
Forward Compatibility	508	(5)
Migration: Routing Algorithms and Addressing	513	(1)
Parameters	514	(3)
Making Multiprotocol Operation Possible	517	(1)
Running over Layer 3 versus Layer 2	518	(1)
Robustness	519	(1)
Determinism versus Stability	520	(1)
Performance for Correctness	521	(1)
In Closing	521	(2)
Glossary	523	(10)
Index	533

Excerpts

Interconnections, Second Editionis about what goes on inside the boxes that move data around the Internet. These boxes are variously called bridges, routers, switches, and hubs. The book also describes the devices that connect to the network. There is considerable confusion in this area. Most of the terminology is ill defined and is used in conflicting ways. The terminology and the specifications tend to be daunting. Some knowledge is spread among many different documents; much is unwritten folk wisdom. Adding to the confusion is dogma. Beliefs are accepted as truth, and questioning any of the dogma is often greeted with hostility. But good engineering demands that we understand what we're doing and why, keep an open mind, and learn from experience. InInterconnections, Second Edition,instead of diving right into the details of one protocol, I first focus on the problems to be solved. I examine various solutions to each of these problems and discuss the engineering trade-offs involved. Then I look at a variety of solutions that have been deployed and compare the approaches. I give technical arguments for any opinions, and if you think I have missed any arguments I welcome email discussion. My email address is at the back of the book, which I hope you will find after having read the book cover to cover. In the first edition, my intention was to help people understand the problems and the general types of solutions, assuming that they would read the specifications to get the details of specific protocols. But people used the book as a reference in addition to using it to understand the issues. So in this edition I have documented many more of the protocols in detail. I believe that to understand something deeply you need to compare it to something else. The first edition was "minimalist" in that I always used only two examples: two types of bridges, bridges versus routers, connection-oriented versus connectionless network layer protocols, and two examples of connectionless protocols (CLNP and IP). In this edition I add a lot more examples, including ATM, IPv6, IPX, AppleTalk, and DECnet. I did this in part because these protocols exist, and it is hard to get information about them. But mostly I did it because the protocols embody interesting ideas that should not be lost. When we design new protocols, we should learn from previous ideas, both good and bad. Also, it takes very little additional effort, after the problem is described generically, to describe several examples. Roadmap to the Book The first four chapters are not significantly different from their counterparts in the first edition, but the rest of the book has been largely rewritten. Chapters 1 through 4 cover general networking concepts, data link issues such as addressing and multiplexing, transparent bridges and the spanning tree algorithm, and source routing bridges. Chapter 5 is completely new and explains how the notion of a switch evolved into a rediscovery of the bridge. It also covers VLANs and fast Ethernet. The remainder of the book concentrates on layer 3 (the network layer). Chapter 6 gives an overview of the network layer. Chapter 7 covers connection-oriented networks, including ATM and X.25. Chapter 8 discusses the issues in a generic connectionless network layer. Chapter 9 covers layer 3 addressing generically and gives a detailed comparison of IP, IPv6, CLNP, DECnet, AppleTalk, and IPX. Chapter 10 covers the information that should appear in a network layer header and contrasts the headers of several protocols. Chapter 11 covers autoconfiguration and neighbor discovery, including protocols such as ARP and DHCP. Chapter 12 covers routing algorithms generically. Chapter 13 discusses the problem of doing longest-prefix matching, which is required i