Udp Helper With Subnet Broadcast Addresses; Udp Helper With Configured Broadcast Addresses - Dell Force10 MXL Blade Configuration Manual

Figure 14-12. UDP helper with All Broadcast Addresses
Packet 1
Destination Address:
255.255.255.255

UDP Helper with Subnet Broadcast Addresses

When the destination IP address of an incoming packet matches the subnet broadcast address of any
interface, the system changes the address to the configured broadcast address and sends it to a matching
interface.
In Figure
address of VLAN 101. If you configured UDP helper and the packet matches the specified UDP port, the
system changes the address to the configured IP broadcast address and floods the packet on VLAN 101.
Packet 2 is sent from host on VLAN 101. It has a broadcast MAC address and a destination IP address of
1.1.1.255. In this case, it is flooded on VLAN 101 in its original condition as the forwarding process is
Layer 2.
Figure 14-13. UDP helper with Subnet Broadcast Addresses
Start Frame
Preamble
Delimiter

UDP Helper with Configured Broadcast Addresses

Incoming packets with a destination IP address matching the configured broadcast address of any interface
are forwarded to the matching interfaces.
In Figure
VLAN 100 and 101. If you enabled UDP helper and the UDP port number matches, the packet is flooded
on both VLANs with an unchanged destination address.
274
| IPv4 Routing
1/1
Ingress interface
IP Address: 2.1.1.1/24
UDP helper enabled
Packet 2
Switched Packet
14-13, Packet 1 has the destination IP address 1.1.1.255, which matches the subnet broadcast
Destination MAC
Source MAC
(01:80:C2:00:00:0E)
TLV 1 TLV 2 TLV 3
Chassis ID Port ID Port Description
14-14, Packet 1 has a destination IP address that matches the configured broadcast address of
1/2
1/3
VLAN 101
IP address: 1.11.1/24
Subnet broadcast address: 1.1.1.255
Configured broadcast address: 1.1.255.255
Hosts on VLAN 100: 1.1.1.2, 1.1.1.3, 1.1.1.4
LLDPDU
Ethernet Type
(0x88CC)
TLV 4 TLV 5
System Name System Description
VLAN 100
IP address: 1.1.0.1/24
Subnet broadcast address: 1.1.0.255
Configured broadcast address: 1.1.255.255
Hosts on VLAN 100: 1.1.0.2, 1.1.0.3, 1.1.0.4
Padding
TLV 6
TLV 7
System Capabilities Management Addr Organizationally Specific
FCS
TLV 127 TLV 0
End of LLDPDU