Concept Guide

Fast Convergence after MSTP Topology Changes
When a port transitions to the Forwarding state as a result of an STP or MSTP topology change, Dell EMC Networking OS sends a general
query out of all ports except the multicast router ports. The host sends a response to the general query and the forwarding database is
updated without having to wait for the query interval to expire.
When an IGMP snooping switch is not acting as a querier, it sends out the general query in response to the MSTP triggered link-layer
topology change, with the source IP address of 0.0.0.0 to avoid triggering querier election.
Egress Interface Selection (EIS) for HTTP and IGMP
Applications
You can use the Egress Interface Selection (EIS) feature to isolate the management and front-end port domains for HTTP and IGMP
trac. Also, EIS enables you to congure the responses to switch-destined trac by using the management port IP address as the source
IP address. This information is sent out of the switch through the management port instead of the front-end port.
The management EIS feature is applicable only for the out-of-band (OOB) management port. References in this section to the
management default route or static route denote the routes congured using the management route command. The management
default route can be either congured statically or returned dynamically by the DHCP client. A static route points to the management
interface or a forwarding router.
Transit trac (destination IP not congured in the switch) that is received on the front-end port with destination on the management port
is dropped and received in the management port with destination on the front-end port is dropped.
Switch-destined trac (destination IP congured in the switch) is:
• Received in the front-end port with destination IP equal to management port IP address or management port subnet broadcast address
is dropped.
• Received in the management port with destination IP not equal to management IP address or management subnet broadcast address is
dropped.
Trac (switch initiated management trac or responses to switch-destined trac with management port IP address as the source IP
address) for user-specied management protocols must exit out of the management port. In this chapter, all the references to trac
indicate switch-initiated trac and responses to switch-destined trac with management port IP address as the source IP address.
In customer deployment topologies, it might be required that the trac for certain management applications needs to exit out of the
management port only. You can use EIS to control and the trac can exit out of any port based on the route lookup in the IP stack.
One typical example is an SSH session to an unknown destination or an SSH connection that is destined to the management port IP
address. The management default route can coexist with front-end default routes. If SSH is specied as a management application, SSH
links to and from an unknown destination uses the management default route.
Protocol Separation
When you congure the application application-type command to congure a set of management applications with TCP/UDP
port numbers to the OS, the following table describes the association between applications and their port numbers.
Internet Group Management Protocol (IGMP)
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