C
HAPTER
18
| General IP Routing
IP Routing and Switching
– 481 –
ES-4500G Series
broadcast to get the destination MAC address from the destination node.
The IP packet can then be sent directly with the destination MAC address.
If the destination belongs to a different subnet on this switch, the packet
can be routed directly to the destination node. However, if the packet
belongs to a subnet not included on this switch, then the packet should be
sent to the next hop router (with the MAC address of the router itself used
as the destination MAC address, and the destination IP address of the
destination node). The router will then forward the packet to the
destination node through the correct path. The router can also use the ARP
protocol to find out the MAC address of the destination node of the next
router as necessary.
N
OTE
:
In order to perform IP switching, the switch should be recognized by
other network nodes as an IP router, either by setting it as the default
gateway or by redirection from another router via the ICMP process.
When the switch receives an IP packet addressed to its own MAC address,
the packet follows the Layer 3 routing process. The destination IP address
is checked against the Layer 3 address table. If the address is not already
there, the switch broadcasts an ARP packet to all the ports on the
destination VLAN to find out the destination MAC address. After the MAC
address is discovered, the packet is reformatted and sent out to the
destination. The reformat process includes decreasing the Time-To-Live
(TTL) field of the IP header, recalculating the IP header checksum, and
replacing the destination MAC address with either the MAC address of the
destination node or that of the next hop router.
When another packet destined to the same node arrives, the destination
MAC can be retrieved directly from the Layer 3 address table; the packet is
then reformatted and sent out the destination port. IP switching can be
done at wire-speed when the destination address entry is already in the
Layer 3 address table.
If the switch determines that a frame must be routed, the route is
calculated only during setup. Once the route has been determined, all
packets in the current flow are simply switched or forwarded across the
chosen path. This takes advantage of the high throughput and low latency
of switching by enabling the traffic to bypass the routing engine once the
path calculation has been performed.
R
OUTING
P
ATH
M
ANAGEMENT
Routing Path Management involves the determination and updating of all
the routing information required for packet forwarding, including:
◆
Handling routing protocols
◆
Updating the routing table
◆
Updating the Layer 3 switching database
Содержание iPECS ES-4526G
Страница 1: ...USER GUIDE User Manual ES 4550G ES 4526G Managed Layer 3 Stackable GE Switch ...
Страница 38: ...CONTENTS 38 ES 4500G Series ...
Страница 58: ...SECTION I Getting Started 58 ES 4500G Series ...
Страница 70: ...CHAPTER 1 Introduction System Defaults 70 ES 4500G Series ...
Страница 84: ...CHAPTER 2 Initial Switch Configuration Managing System Files 84 ES 4500G Series Success Console ...
Страница 86: ...SECTION I Web Configuration 86 ES 4500G Series Multicast Filtering on page 413 ...
Страница 196: ...CHAPTER 6 VLAN Configuration Configuring MAC based VLANs 196 ES 4500G Series ...
Страница 204: ...CHAPTER 7 Address Table Settings Clearing the Dynamic Address Table 204 ES 4500G Series ...
Страница 228: ...CHAPTER 8 Spanning Tree Algorithm Configuring Interface Settings for MSTP 228 ES 4500G Series ...
Страница 230: ...CHAPTER 9 Rate Limit Configuration 230 ES 4500G Series Figure 106 Configuring Rate Limits ...
Страница 260: ...CHAPTER 12 Quality of Service Attaching a Policy Map to a Port 260 ES 4500G Series ...
Страница 478: ...CHAPTER 17 IP Configuration Setting the Switch s IP Address IP Version 6 478 ES 4500G Series ...
Страница 528: ...CHAPTER 20 IP Services Forwarding UDP Service Requests 528 ES 4500G Series ...
Страница 584: ...CHAPTER 21 Unicast Routing Configuring the Open Shortest Path First Protocol Version 2 584 ES 4500G Series ...
Страница 614: ...CHAPTER 22 Multicast Routing Configuring PIMv6 for IPv6 614 ES 4500G Series ...
Страница 628: ...CHAPTER 23 Using the Command Line Interface CLI Command Groups 628 ES 4500G Series ...
Страница 702: ...CHAPTER 26 SNMP Commands 702 ES 4500G Series ...
Страница 710: ...CHAPTER 27 Remote Monitoring Commands 710 ES 4500G Series ...
Страница 868: ...CHAPTER 34 Port Mirroring Commands Local Port Mirroring Commands 868 ES 4500G Series ...
Страница 890: ...CHAPTER 37 Address Table Commands 890 ES 4500G Series ...
Страница 1066: ...CHAPTER 43 LLDP Commands 1066 ES 4500G Series ...
Страница 1076: ...CHAPTER 44 Domain Name Service Commands 1076 ES 4500G Series ...
Страница 1286: ...CHAPTER 49 Multicast Routing Commands PIM Multicast Routing 1286 ES 4500G Series ...
Страница 1288: ...SECTION I Appendices 1288 ES 4500G Series ...
Страница 1293: ...APPENDIX A Software Specifications Management Information Bases 1293 ES 4500G Series UDP MIB RFC 2013 ...
Страница 1294: ...APPENDIX A Software Specifications Management Information Bases 1294 ES 4500G Series ...
Страница 1327: ...ES 4526G ES 4550G E042011 ST R01 150200000149A ...
Страница 1328: ...APRIL 2011 ISSUE 1 0 ...