Cisco Catalyst 3560-X User Manual

1-6
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-25303-03
Chapter 1 Configuring Optional Spanning-Tree Features
Understanding Optional Spanning-Tree Features
How CSUF Works
CSUF ensures that one link in the stack is elected as the path to the root. As shown in Figure 1-5, the
stack-root port on Switch 1 provides the path to the root of the spanning tree. The alternate stack-root
ports on Switches 2 and 3 can provide an alternate path to the spanning-tree root if the current stack-root
switch fails or if its link to the spanning-tree root fails.
Link 1, the root link, is in the spanning-tree forwarding state. Links 2 and 3 are alternate redundant links
that are in the spanning-tree blocking state. If Switch 1 fails, if its stack-root port fails, or if Link 1 fails,
CSUF selects either the alternate stack-root port on Switch 2 or Switch 3 and puts it into the forwarding
state in less than 1 second.
Figure 1-5 Cross-Stack UplinkFast Topology
When certain link loss or spanning-tree events occur (described in “Events that Cause Fast Convergence”
section on page 1-7), the Fast Uplink Transition Protocol uses the neighbor list to send fast-transition
requests to stack members.
The switch sending the fast-transition request needs to do a fast transition to the forwarding state of a
port that it has chosen as the root port, and it must obtain an acknowledgement from each stack switch
before performing the fast transition.
Switch 1
Spanning-
tree root
Backbone
Switch stack
StackWise Plus
port connections
159891
Switch 2 StackWise Plus
port connections
Forward
Link 1
(Root link)
Link 2
(Alternate
redundant
link)
Link 3
(Alternate
redundant
link)
100 or 1000 Mb/s 100 or 1000 Mb/s 100 or 1000 Mb/s
Forward
Forward
Switch 3 StackWise Plus
port connections
Stack-root port
Alternate stack-
root port
Alternate stack-
root port

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)