Cisco Catalyst 4948 User Manual

22 Cisco LAN Switching Configuration Handbook
e. QoS
■ Configure QoS on every switch in your network. QoS must be properly
supported end-to-end. See section “13-2: QoS Configuration,” in Chapter
13, “Quality of Service.”
■ Extend the QoS trust boundary to edge devices (IP phones, for example)
that can provide trust.
■ Use policers to control nonmission-critical traffic flows.
f. Redundant switch modules
■ Consider using redundant supervisors in server farm switches where hosts
are single-attached (one NIC).
■ If redundant uplinks are provided at each network layer, two physically sep-
arate switches will always provide redundancy. Use redundant supervisors in
distribution or core layer switches where only single uplinks are available.
■ Use high-availability redundancy between supervisors in a chassis. Enable
versioning so that the OS can be upgraded without a switch downtime. See
section “3-6: Redundant Supervisors,” in Chapter 3, “Supervisor Engine
Configuration.”
g. Port security, authentication
■ You can control the end-user MAC address or the number of users connect-
ed to an access layer switch port with port security. See section “11-3: Port
Security,” in Chapter 11.
■ Authenticate users at the access layer switch ports. Section “11-8: 802.1X
Port Authentication,” in Chapter 11 describes how to configure a port to
require a login or certificate for user authentication before granting access
to the network.
■ Control access to VLANs with VLAN ACLs. See section “11-4: VLAN
Access Control Lists,” in Chapter 11.
■ Dynamic ARP Inspection (DAI) is a security feature that validates ARP
packets in a network. See section “11-9: Layer 2 Security,” in Chapter 11.
■ DHCP Snooping provides the security against the Denial-of-Service (DoS)
attacks. See section “11-9: Layer 2 Security,” in Chapter 11.
■ IP Source Guard prevents IP spoofing by allowing only the IP addresses that
are obtained through DHCP Snooping on a particular port. See section “11-
9: Layer 2 Security,” in Chapter 11.

Cisco Catalyst 4948 Specifications

General

Switching Capacity	136 Gbps
Forwarding Rate	102 Mpps
Rack Units	1U
MAC Address Table Size	32, 000 entries
Authentication Method	RADIUS, TACACS+
RAM	256 MB
Flash Memory	64 MB
Power Device	Internal power supply
Voltage Required	100-240 VAC
Weight	16.5 lbs
Operating Humidity	10% to 85% non-condensing
Ports	48 x 10/100/1000
Power Supply	Internal
Layer Support	Layer 3
Jumbo Frame Support	Yes (up to 9216 bytes)
Routing Protocol	RIP, OSPF, EIGRP, BGP
Remote Management Protocol	SNMP, Telnet, SSH
Features	VLAN support, QoS
Compliant Standards	IEEE 802.3, IEEE 802.3u, IEEE 802.3ab, IEEE 802.1Q, IEEE 802.1p
Operating Temperature	32 °F to 104 °F (0 °C to 40 °C)