For which two protocols can PortFast alleviate potential host startup issues? (Choose two.)
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A. B. C. D. E.AB
PortFast is a feature on Cisco switches that is used to speed up the convergence time of Spanning Tree Protocol (STP) by bypassing the listening and learning phases. It is used on access ports where only end hosts are connected and not switches.
PortFast can alleviate potential host startup issues for the following protocols:
A. DHCP - PortFast can be used to allow a host to receive a DHCP IP address immediately upon startup. Without PortFast, the host's access port will transition through the listening and learning phases of STP, which can take up to 50 seconds to complete. During this time, the host will not be able to receive an IP address from a DHCP server.
B. DNS - PortFast can be used to speed up the resolution of DNS queries for hosts that use DHCP to obtain their IP address. Without PortFast, the host's access port will transition through the listening and learning phases of STP, which can cause a delay in DNS resolution. With PortFast enabled, the host's access port will immediately transition to the forwarding state, allowing the host to quickly resolve DNS queries.
C. OSPF - PortFast is not used to alleviate potential host startup issues for OSPF. OSPF is a routing protocol that runs between routers and not hosts.
D. RIP - PortFast is not used to alleviate potential host startup issues for RIP. RIP is a routing protocol that runs between routers and not hosts.
E. CDP - PortFast is not used to alleviate potential host startup issues for CDP. CDP is a protocol used by Cisco devices to share information about directly connected