Cisco 500 Series Administration Guide

IP Configuration
IPv4 Management and Interfaces
361 Cisco 500 Series Managed Switch Administration Guide
18
STEP 6 Device forwards DHCPOFFER, DHCPACK, or DHCPNAK.
The following summarizes how DHCP packets are handled from both trusted and
untrusted ports. The DHCP Snooping Binding database is stored in non-volatile
memory.
DHCP Snooping Packet Handling
Packet Type Arriving from
Untrusted Ingress
Interface
Arriving from Trusted Ingress
Interface
DHCPDISCOVER Forward to trusted
interfaces only.
Forwarded to trusted interfaces
only.
DHCPOFFER Filter. Forward the packet according to
DHCP information. If the
destination address is unknown
the packet is filtered.
DHCPREQUEST Forward to trusted
interfaces only.
Forward to trusted interfaces
only.
DHCPACK Filter. Same as DHCPOFFER and an
entry is added to the DHCP
Snooping Binding database.
DHCPNAK Filter. Same as DHCPOFFER. Remove
entry if exists.
DHCPDECLINE Check if there is
information in the
database. If the
information exists and
does not match the
interface on which the
message was
received, the packet
is filtered. Otherwise
the packet is
forwarded to trusted
interfaces only, and
the entry is removed
from database.
Forward to trusted interfaces only

Cisco 500 Series Specifications

General

Model	Cisco 500 Series
Category	Switch
Mounting	Rack-mountable
Management	Web-based, CLI, SNMP
Ports	24, 48
Port Speed	10/100/1000 Mbps
PoE Support	Available on some models
Switching Capacity	Up to 176 Gbps
MAC Address Table Size	16, 000 entries
Security	ACLs, 802.1X
Quality of Service (QoS)	Yes
Dimensions	Varies by model
Weight	Varies by model
Humidity	10% to 90% non-condensing
Power Supply	Internal
Power Consumption	Varies by model
Jumbo Frame Support	Up to 9216 bytes