Cisco Catalyst 3560-X User Manual

1-3
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-25303-03
Chapter 1 Configuring QoS
Understanding QoS
Figure 1-1 QoS Classification Layers in Frames and Packets
All switches and routers that access the Internet rely on the class information to provide the same
forwarding treatment to packets with the same class information and different treatment to packets with
different class information. The class information in the packet can be assigned by end hosts or by
switches or routers along the way, based on a configured policy, detailed examination of the packet, or
both. Detailed examination of the packet is expected to happen closer to the edge of the network so that
the core switches and routers are not overloaded with this task.
Switches and routers along the path can use the class information to limit the amount of resources
allocated per traffic class. The behavior of an individual device when handling traffic in the DiffServ
architecture is called per-hop behavior. If all devices along a path provide a consistent per-hop behavior,
you can construct an end-to-end QoS solution.
Implementing QoS in your network can be a simple or complex task and depends on the QoS features
offered by your internetworking devices, the traffic types and patterns in your network, and the
granularity of control that you need over incoming and outgoing traffic.
206582
Encapsulated Packet
Layer 2
header
IP header
3 bits used for CoS
Data
Layer 2 ISL Frame
ISL header
(26 bytes)
Encapsulated frame 1...
(24.5 KB)
FCS
(4 bytes)
Layer 2 802.1Q and 802.1p Frame
Preamble
Start frame
delimiter
DA
Len
SA Ta g PT Data FCS
Layer 3 IPv4 Packet
Version
length
To S
(1 byte)
ID Offset TTL Proto FCS IP-SA IP-DA Data
3 bits used for CoS (user priority)
IP precedence or DSCP
Flow
label
Layer 3 IPv6 Packet
Version
Traffic class
(1 byte)
Payload
length
Next
header
HOP
limit
Source
address
Dest.
address
IP precedence or DSCP

Cisco Catalyst 3560-X Specifications

General

Enclosure Type	Rack-mountable - 1U
Subtype	Gigabit Ethernet
Ports	48 x 10/100/1000 + 4 x SFP
Flash Memory	64 MB
Power Device	Internal power supply
Voltage Required	AC 120/230 V (50/60 Hz)
Operating System	Cisco IOS
Device Type	Switch
Performance	Switching capacity: 128 Gbps
Jumbo Frame Support	Yes
Routing Protocol	RIP-1, RIP-2, EIGRP
Remote Management Protocol	SNMP 1, RMON 1, RMON 2, RMON 3, RMON 9, Telnet, SNMP 3, HTTP, HTTPS
Features	DHCP support, VLAN support, QoS, IPv6 support, Syslog
Compliant Standards	IEEE 802.3, IEEE 802.3u, IEEE 802.3z, IEEE 802.1D, IEEE 802.1Q, IEEE 802.3ab, IEEE 802.1p, IEEE 802.3af, IEEE 802.3x, IEEE 802.3ad, IEEE 802.1w, IEEE 802.1x, IEEE 802.1s, IEEE 802.3ah, IEEE 802.1ag, IEEE 802.3at
Stacking	Stackable
Security Features	SSH, RADIUS, TACACS+
Management	CLI
Dimensions (H x W x D)	17.5 in
Operating Temperature	32 to 113 °F (0 to 45 °C)
Humidity	10 - 95% (non-condensing)