
Queueing strategy: fifo
Input Statistics:
0 packets, 0 bytes
Time since last interface status change: 00:07:44
Configurations Using UDP Helper
When you enable UDP helper and the destination IP address of an incoming packet is a broadcast address, Dell Networking OS
suppresses the destination address of the packet.
The following sections describe various configurations that employ UDP helper to direct broadcasts.
•
UDP Helper with Broadcast-All Addresses
•
UDP Helper with Subnet Broadcast Addresses
•
UDP Helper with Configured Broadcast Addresses
•
UDP Helper with No Configured Broadcast Addresses
UDP Helper with Broadcast-All Addresses
When the destination IP address of an incoming packet is the IP broadcast address, Dell Networking OS rewrites the address to
match the configured broadcast address.
In the following illustration:
1.
Packet 1 is dropped at ingress if you did not configure UDP helper address.
2.
If you enable UDP helper (using the
ip udp-helper udp-port
command), and the UDP destination port of the packet
matches the UDP port configured, the system changes the destination address to the configured broadcast 1.1.255.255 and
routes the packet to VLANs 100 and 101. If you do not configure an IP broadcast address (using the
ip udp-broadcast-
address
command) on VLANs 100 or 101, the packet is forwarded using the original destination IP address 255.255.255.255.
Packet 2, sent from a host on VLAN 101 has a broadcast MAC address and IP address. In this case:
1.
It is flooded on VLAN 101 without changing the destination address because the forwarding process is Layer 2.
2.
If you enabled UDP helper, the system changes the destination IP address to the configured broadcast address 1.1.255.255 and
forwards the packet to VLAN 100.
3.
Packet 2 is also forwarded to the ingress interface with an unchanged destination address because it does not have broadcast
address configured.
Figure 55. UDP Helper with Broadcast-All Addresses
IPv4 Routing
415
Summary of Contents for S4048-ON
Page 1: ...Dell Configuration Guide for the S4048 ON System 9 9 0 0 ...
Page 146: ...Figure 14 BFD Three Way Handshake State Changes 146 Bidirectional Forwarding Detection BFD ...
Page 522: ...Figure 87 Configuring Interfaces for MSDP 522 Multicast Source Discovery Protocol MSDP ...
Page 523: ...Figure 88 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 523 ...
Page 528: ...Figure 91 MSDP Default Peer Scenario 1 528 Multicast Source Discovery Protocol MSDP ...
Page 529: ...Figure 92 MSDP Default Peer Scenario 2 Multicast Source Discovery Protocol MSDP 529 ...
Page 530: ...Figure 93 MSDP Default Peer Scenario 3 530 Multicast Source Discovery Protocol MSDP ...
Page 633: ...Policy based Routing PBR 633 ...
Page 777: ...Figure 119 Single and Double Tag TPID Match Service Provider Bridging 777 ...
Page 778: ...Figure 120 Single and Double Tag First byte TPID Match 778 Service Provider Bridging ...