Dhcp persistence – Rockwell Automation 1783-Mxxx Stratix 8000 and 8300 Ethernet Managed Switches User Manual User Manual
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Rockwell Automation Publication 1783-UM003I-EN-P - March 2014
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Switch Software Features Chapter 3
You can configure an EtherChannel in one of these modes: Port Aggregation
Protocol (PAgP), Link Aggregation Control Protocol (LACP), or On.
Configure both ends of the EtherChannel in the same mode.
• When you configure one end of an EtherChannel in either PAgP or LACP
mode, the system negotiates with the other end of the channel to
determine which ports become active. Incompatible ports are suspended.
Instead of a suspended state, the local port is put into an independent state
and continues to carry data traffic as any other single link. The port
configuration does not change, but the port does not participate in the
EtherChannel.
• When you configure an EtherChannel in the On mode, no negotiations
take place. The switch forces all compatible ports to become active in the
EtherChannel. The other end of the channel (on the other switch) must
also be configured in the On mode; otherwise, packet loss can occur.
If a link within an EtherChannel fails, traffic previously carried over that failed
link moves to the remaining links within the EtherChannel. If traps are enabled
on the switch, a trap is sent for a failure that identifies the switch, the
EtherChannel, and the failed link. Inbound broadcast and multicast packets on
one link in an EtherChannel are blocked from returning on any other link of the
EtherChannel.
DHCP Persistence
Every device in an IP-based network must have a unique IP address. The
Dynamic Host Configuration Protocol (DHCP) automatically assigns IP
address information from a pool of available addresses to newly connected
devices (DHCP clients) in the network. If a device leaves and then re-joins the
network, the device receives the next available IP address, which can be the same
address that it had before.
The switch can be set to operate as a DHCP server to provide DHCP
persistence. With DHCP persistence, you can assign a specific IP address to each
port, ensuring that the device attached to a given port receives the same IP
address.
The DHCP Server also serves addresses to BOOTP clients.
IMPORTANT
To make sure DHCP persistence works correctly, follow the application rules.