臺灣博碩士論文加值系統

虛擬路由協定是被設計來避免在區域網路上以靜態路由為主的單點故障，原本的VRRP並不支援網路流量的負載平衡，本文討論EVRRP，Enhanced VRRP，EVRRP提供了有效率的多點叢集與對稱式的路由負載平衡．每個路由器定時的交換資料以決定誰是主要或是備份的路由器，主要路由器除了負責本身的路由交通外亦擔任了利用ICMP導向訊息方式將流量分散到各個備份路由器的工作，而備份路由器除了處理從主要路由器導來的流量外，亦隨時監控主要路由，一但主要路由器發生故障，會有一個備份路由器升級成主要路由並用Gratuitous ARP封包通知網路上的主機將原本導向發生錯誤的主要路由的流量重新導向自己，除了負載平衡的設計外，新增加的選舉協定可以加速原本VRRP的選舉方式並且縮短錯誤移轉的時間，本文亦提供了對於EVRRP全面性的評估。

Virtual Router Redundancy Protocol (VRRP) is designed to eliminate the single point of failure in the static default routing environment in LAN. The original VRRP protocol does not support load balancing for both incoming and outgoing traffic. This paper describes EVRRP, i.e. Enhanced VRRP. EVRRP supports an efficient multiple-node cluster and symmetric load balancing among routers. Each router periodically exchanges information to determine the status of the master and backups. The master router distributes and redirects the traffic to one of the backup routers by ICMP redirect message. Backup routers accept the traffic from the master and one of the backup routers takes over the master traffic using a gratuitous ARP message when the master fails. The improved election protocol speeds up the original VRRP election protocol and shortens the failover time by adding a new state in the previous VRRP state diagram and a new protocol type. An extensive evaluation of the EVRRP protocol is described in the paper.

Chapter 1 Introduction 1
1.1 Router Cluster 2
1.2 Load Balancing 2
1.3 Change of Configurations 3
Chapter 2 Related Works 4
2.1 VRRP in RFC 2338 (obsolete) 4
2.2 VRRP in RFC 3768 5
2.3 HSRP 5
Chapter 3 EVRRP Protocol 6
3.1 Protocol Description 6
3.1.1 Advertisement 6
3.1.2 Election 7
3.1.3 Using ICMP Redirection in Load Balancing 7
3.1.4 Using ARP Poison in Router Redundancy 10
3.1.5 State Diagram 13
3.2 Compatibility with Original VRRP 14
3.2.1 VRRP Router Acts as Backup Router 15
3.2.2 VRRP Router Acts as Master Router 15
3.2.3 VRRP Router Receives Election Packets 15
Chapter 4 Evaluation 17
4.1 Testing Environment Setup 17
4.2 Data Collection 18
4.3 Load Balancing Capability Test 18
4.4 CPU Usage Comparisons 21
4.5 EVRRP Compatibility Test 22
4.6 Traffic Consumed by extra ICMP packets 23
4.7 Fail-over Test 24
4.7.1 Fail-over Test Environment Setup 25
4.7.2 Fail-over Timeout 26
4.8 Traffic Redirection and Balancing 27
Chapter 5 Concluding Remarks 29
References 30
Appendix 31
1 Implementation Issues 31
1.1 Packet Format 31
1.2 ICMP Redirection 32
1.3 ARP Poison 32
2 State Diagram for ICMP Redirection 33
3 EVRRP Protocol Description 34
3.1 Initial State 34
3.2 Backup State 34
3.3 Election State 35
3.4 Master State 36

[1]J. Etienne, “VRRPd: overview, implementation and usage,” Ottawa Linux Symposium 2001, July 2001.
[2]J. Ranta, “Router Redundancy and Scalability Using Clustering,” Seminar on Internetworking, Spring 2004, eds. A. Ylä-Jääski, N. Kasinskaja, [Online] Available: http://www.tml.hut.fi/Studies/T-110.551/2004/papers/Ranta.pdf, June 2004.
[3]R. Hinden, D. Mitzel, P. Hunt, P. Higginson, M. Shand, A. Lindem, S. Knight, D. Weaver and D. Whipple, “Virtual Router Redundancy Protocol,” Internet Draft, draft-ietf-vrrpspec-v2-06.txt, Feburary 2002.
[4][VRRP] R. Hinden, Ed., “Virtual Router Redundancy Protocol,“ RFC 3768, April 2004.
[5][VRRP] S. Knight, D. Weaver, D.Whipple, R.Hinden, D. Mitzel, P. Hunt, P. Higginson, M. Shand, and A. Lindem, “Virtual Router Redundancy Protocol”, RFC 2338, April 1998.
[6][HSRP] T. Li, B. Cole, P. Morton and D. Li, “Cisco Hot Standby Router Protocol (HSRP),” RFC 2281, March 1998.
[7][ICMP] J. Postel, “Internet Control Message Protocol,” RFC 792, September 1981.
[8][ARP] D. Plummer, “An Ethernet Address Resolution Protocol,” RFC 826, November 1982.
[9]VRRPd Linux Implementation, ImageStream Internet Solution, Inc., http://www.imagestream.com/VRRP.html
[10]Chariot, NetIQ Corporation, http://www.netiq.com/products/chr/default.asp
[11]Gentoo Linux, Gentoo Foundation, Inc., http://www.gentoo.org
[12]Avalanche 220™ and Reflector 220™, Spirent Communications, http://www.spirentcom.com/