HP J9729A User Manual (English)

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Example 37 Output for show ip irdp

HP Switch# show ip irdp

Status and Counters - ICMP Router Discovery Protocol

Global Status : Disabled

VLAN Name Status Advertising Min int Max int Holdtime Preference

Address (sec) (sec) (sec)

------------- -------- ----------- ------- ------- -------- ----------

DEFAULT_VLAN Enabled multicast 450 600 1800 0

VLAN20 Enabled multicast 450 600 1800 0

VLAN30 Enabled multicast 450 600 1800 0

Configuring DHCP relay

Overview

The Dynamic Host Configuration Protocol (DHCP) is used for configuring hosts with IP address and

other configuration parameters without user intervention. The protocol is composed of three

components:

• DHCP client

• DHCP server

• DHCP relay agent

The DHCP client sends broadcast request packets to the network; the DHCP servers respond with

broadcast packets that offer IP parameters, such as an IP address for the client. After the client

chooses the IP parameters, communication between the client and server is by unicast packets.

HP routing switches provide the DHCP relay agent to enable communication from a DHCP server

to DHCP clients on subnets other than the one the server resides on. The DHCP relay agent transfers

DHCP messages from DHCP clients located on a subnet without a DHCP server to other subnets.

It also relays answers from DHCP servers to DHCP clients.

The DHCP relay agent is transparent to both the client and the server. Neither side is aware of the

communications that pass through the DHCP relay agent. As DHCP clients broadcast requests, the

DHCP relay agent receives the packets and forwards them to the DHCP server. During this process,

the DHCP relay agent increases the hop count by one before forwarding the DHCP message to

the server. A DHCP server includes the hop count from the DHCP request that it receives in the

response that it returns to the client.

DHCP packet forwarding

The DHCP relay agent on the routing switch forwards DHCP client packets to all DHCP servers that

are configured in the table administrated for each VLAN.

Unicast forwarding

The packets are forwarded using unicast forwarding if the IP address of the DHCP server is a

specific host address. The DHCP relay agent sets the destination IP address of the packet to the IP

address of the DHCP server and forwards the message.

Broadcast forwarding

The packets are forwarded using broadcast forwarding if the IP address of the DHCP server is a

subnet address or IP broadcast address (255.255.255.255.) The DHCP relay agent sets the DHCP

server IP address to broadcast IP address and is forwarded to all VLANs with configured IP interfaces

(except the source VLAN.)

Configuring DHCP relay 63

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HP J9729A Specifications

General

Category	Switch
Switching Capacity	128 Gbps
Forwarding Rate	95.2 Mpps
Jumbo Frame Support	Yes
Power over Ethernet (PoE)	No
Power Supply	Internal
Model	HP J9729A
Uplink Ports	4 x SFP+
MAC Address Table Size	16384 entries
Management	Web, CLI, SNMP
Form Factor	Rack-mountable
Ports	48 x 10/100/1000 ports