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 49. UDP Helper with Broadcast-All Addresses
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 matching
interface.
In the following illustration, Packet 1 has the destination IP address 1.1.1.255, which matches the subnet
broadcast 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 the 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 50. UDP Helper with Subnet Broadcast Addresses
496
IPv4 Routing
Summary of Contents for S4820T
Page 1: ...Dell Configuration Guide for the S4820T System 9 8 0 0 ...
Page 282: ...Dell 282 Control Plane Policing CoPP ...
Page 622: ...Figure 81 Configuring Interfaces for MSDP 622 Multicast Source Discovery Protocol MSDP ...
Page 623: ...Figure 82 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 623 ...
Page 629: ...Figure 86 MSDP Default Peer Scenario 2 Multicast Source Discovery Protocol MSDP 629 ...
Page 630: ...Figure 87 MSDP Default Peer Scenario 3 630 Multicast Source Discovery Protocol MSDP ...
Page 751: ...10 11 5 2 00 00 05 00 02 04 Member Ports Te 1 2 1 PIM Source Specific Mode PIM SSM 751 ...
Page 905: ...Figure 112 Single and Double Tag First byte TPID Match Service Provider Bridging 905 ...
Page 979: ...6 Member not present 7 Member not present Stacking 979 ...
Page 981: ...storm control Storm Control 981 ...
Page 1103: ...Figure 134 Setup OSPF and Static Routes Virtual Routing and Forwarding VRF 1103 ...