Udp Helper With Configured Broadcast Addresses - Dell Force10 C150 Configuration Manual

In Figure
address of VLAN 101. If UDP helper is configured and the packet matches the specified UDP port, then
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 21-15. UDP helper with Subnet Broadcast Addresses
Preamble Start Frame
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 UDP helper is enabled and the UDP port number matches, the packet is flooded on
both VLANs with an unchanged destination address.
Packet 2 is sent from a host on VLAN 101. It has broadcast MAC address and a destination IP address that
matches the configured broadcast address on VLAN 101. In this case, Packet 2 is flooded on VLAN 101
with the destination address unchanged because the forwarding process is Layer 2. If UDP helper is
enabled, the packet is flooded on VLAN 100 as well.
Figure 21-16. UDP Helper with Configured Broadcast Addresses
Packet 1
Destination Address:
1.1.255.255
480 | IPv4 Addressing
21-15, 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
21-16, Packet 1 has a destination IP address that matches the configured broadcast address of
1/1
Ingress interface
IP Address: 2.1.1.1/24
UDP helper enabled
Packet 2
Switched Packet
Destination Address:
1.1.255.255
Ethernet Type LLDPDU
(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:
Hosts on VLAN 100: 1.1.0.2, 1.1.0.3, 1.1.0.4
1/2
1/3
VLAN 101
IP address: 1.11.1/24
Subnet broadcast address: 1.1.1.255
Configured broadcast address:
Hosts on VLAN 100: 1.1.1.2, 1.1.1.3, 1.1.1.4
Padding
TLV 6 TLV 7
System Capabilities Management Addr Organizationally Specific
1.1.255.255
1.1.255.255
fnC0048mp
FCS
TLV 127 TLV 0
End of LLDPDU