The Ip Packet Flow - Dell PowerConnect B-RX Configuration Manual

7

The IP packet flow

The IP packet flow

Figure 5
FIGURE 5
Figure 5
1. When the device receives an IP packet, the device checks for IP ACL filters on the receiving
2. If the packet is not denied, the device checks for Policy Based Routing (PBR). If the packet
3. If the incoming packet does not match PBR rules, the device looks in the hardware IP routing
146
Shows how an IP packet moves through a device.
IP Packet flow through a device
IP ACLs
Incoming
(hardware)
Port
Permit
PBR
(hardware)
Yes
No
Next Hop
Table
(hardware)
IP Routing
(hardware)
Match Forward to CPU
Shows the following packet flow.
interface. If a deny filter on the interface denies the packet, the device discards the packet and
performs no further processing. If logging is enabled for the filter, then the device generates a
Syslog entry and SNMP trap message.
matches a PBR policy applied on the incoming port, the PBR processing is performed and
either drops the packet or forwards it to a port, based on the route map rules.
table to perform IP routing. The hardware routing table is pre-loaded with the complete routing
table, except for the directly connected host entries. Default and statically defined routes are
also pre-loaded in the hardware routing table. If the incoming packet matches a route entry,
the packet is routed according to the information provided in the route entry. The ECMP and
trunk load balancing is done by the hardware, if needed, to select the outgoing port.
Deny
Drop
Lowest
Metric
Directly
connected
host
No Match
forwarding
cache
(software)
ECMP and
Trunk Load
Balancing
(hardware)
Outgoing
Port
ARP
Static ARP
Table
Table
(software)
Lowest
IP Route
Admin.
Table
Distance
(software)
BigIron RX Series Configuration Guide
RIP
OSPF
BGP4
53-1001810-01