362
C
HAPTER
22: C
ONFIGURING
IP P
ERFORMANCE
Configure Fast
Forwarding
Message forwarding efficiency is a key feature evaluating router performance.
According to regular flow, when a message arrives, the router will copy it from the
interface memory to the main CPU. The CPU specifies the network ID from the IP
address, consults with the routing table to get the best path to forward the
message, and creates MAC frame suitable for output of the message. The created
MAC frame is copied to the output queue via DMA (Direct Memory Access), and
during this process the main system bus is passed twice. This process can be
repeated for message forwarding.
In the Fast forwarding, cache is used to process messages. After the first message
is forwarded by searching routing table, corresponding exchange information is
generated in the cache, and forwarding of the following same messages can be
realized by directly searching the cache. This practice greatly simplifies the queuing
of IP messages, cuts down the route finding time and improves forwarding
throughput of IP messages. Since the forwarding table in the cache has been
optimized, much quicker searching speed can be obtained.
The 3Com Router supports Fast forwarding on various high-speed link interfaces,
such as Ethernet, synchronous PPP, frame relay and HDLC.
Besides, the 3Com Router also supports Fast forwarding when firewall is
configured.
Fast forwarding implemented via the 3Com Router contains the following
features:
■
Support fast forwarding on all types of high-speed link interfaces, including
Ethernet, synchronous PPP, frame-relay and HDLC etc.
■
Provide fast forwarding when the firewall is configured.
■
Support load sharing and improve packets forwarding efficiency greatly.
The performance of Fast forwarding sometimes will be affected by some
characteristics such as message queue management and message header
compression. Fast forwarding is not conducted for fragmented messages.
Fast-forwarding Configuration includes:
■
Enable/Disable fast-forwarding on an interface
■
Configure fast-forwarding table size
1
Enable/Disable fast-forwarding on an interface
You can disable fast-forwarding as needed. For example, if load sharing is required
when forwarding packets, fast-forwarding should be disabled in the forwarding
direction of the interface.
Perform the following configuration in interface view.
Table 395
Enable/Disable fast-forwarding on an interface
Operation
Command
Enable fast-forwarding in both directions of the
interface
ip fast-forwarding
Enable fast-forwarding on the inbound interface
ip fast-forwarding inbound
Enable fast-forwarding on the outbound interface
ip fast-forwarding outbound
Summary of Contents for 3036
Page 1: ...http www 3com com 3Com Router Configuration Guide Published March 2004 Part No 10014299 ...
Page 4: ...VPN 615 RELIABILITY 665 QOS 681 DIAL UP 721 ...
Page 6: ...2 ABOUT THIS GUIDE ...
Page 7: ...I GETTING STARTED Chapter 1 3Com Router Introduction Chapter 2 3Com Router User Interface ...
Page 8: ...4 ...
Page 16: ...12 CHAPTER 1 3COM ROUTER INTRODUCTION ...
Page 34: ...30 ...
Page 60: ...56 CHAPTER 3 SYSTEM MANAGEMENT ...
Page 98: ...94 CHAPTER 6 DISPLAY AND DEBUGGING TOOLS ...
Page 110: ...106 ...
Page 114: ...110 CHAPTER 8 INTERFACE CONFIGURATION OVERVIEW ...
Page 158: ...154 CHAPTER 10 CONFIGURING WAN INTERFACE ...
Page 168: ...164 ...
Page 188: ...184 CHAPTER 13 CONFIGURING PPPOE CLIENT ...
Page 192: ...188 CHAPTER 14 CONFIGURING SLIP Router ip route static 0 0 0 0 0 0 0 0 10 110 0 1 ...
Page 248: ...244 CHAPTER 16 CONFIGURING LAPB AND X 25 ...
Page 320: ...316 ...
Page 330: ...326 CHAPTER 20 CONFIGURING IP ADDRESS ...
Page 362: ...358 CHAPTER 21 CONFIGURING IP APPLICATION ...
Page 374: ...370 CHAPTER 23 CONFIGURING IP COUNT ...
Page 406: ...402 CHAPTER 25 CONFIGURING DLSW ...
Page 408: ...404 ...
Page 452: ...448 CHAPTER 29 CONFIGURING OSPF ...
Page 482: ...478 CHAPTER 30 CONFIGURING BGP ...
Page 494: ...490 CHAPTER 31 CONFIGURING IP ROUTING POLICY ...
Page 502: ...498 ...
Page 508: ...504 CHAPTER 33 IP MULTICAST ...
Page 514: ...510 CHAPTER 34 CONFIGURING IGMP ...
Page 526: ...522 CHAPTER 36 CONFIGURING PIM SM ...
Page 528: ...524 ...
Page 532: ...528 CHAPTER 37 CONFIGURING TERMINAL ACCESS SECURITY ...
Page 550: ...546 CHAPTER 38 CONFIGURING AAA AND RADIUS PROTOCOL ...
Page 590: ...586 CHAPTER 40 CONFIGURING IPSEC ...
Page 599: ...IX VPN Chapter 42 Configuring VPN Chapter 43 Configuring L2TP Chapter 44 Configuring GRE ...
Page 600: ...596 ...
Page 638: ...634 CHAPTER 43 CONFIGURING L2TP ...
Page 649: ...X RELIABILITY Chapter 45 Configuring a Standby Center Chapter 46 Configuring VRRP ...
Page 650: ...646 ...
Page 666: ...662 ...
Page 670: ...666 CHAPTER 47 QOS OVERVIEW ...
Page 700: ...696 CHAPTER 49 CONGESTION MANAGEMENT ...
Page 706: ...702 CHAPTER 50 CONGESTION AVOIDANCE ...
Page 707: ...XII DIAL UP Chapter 51 Configuring DCC Chapter 52 Configuring Modem ...
Page 708: ...704 ...
Page 762: ...758 CHAPTER 52 CONFIGURING MODEM ...