Brocade Communications Systems Brocate Ethernet Access Switch 6910 - Manual (Page 56)

6 Brocade 6910 Ethernet Access Switch Configuration Guide
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Description of Software Features
1
IP Address
Filtering
Access to insecure ports can be controlled using DHCP Snooping which filters ingress traffic based
on static IP addresses and addresses stored in the DHCP Snooping table. Traffic can also be
restricted to specific source IP addresses or source IP/MAC address pairs based on static entries
or entries stored in the DHCP Snooping table.
IEEE 802.1D
Bridge
The switch supports IEEE 802.1D transparent bridging. The address table facilitates data switching
by learning addresses, and then filtering or forwarding traffic based on this information.
Store-and-
Forward
Switching
The switch copies each frame into its memory before forwarding them to another port. This ensures
that all frames are a standard Ethernet size and have been verified for accuracy with the cyclic
redundancy check (CRC). This prevents bad frames from entering the network and wasting
bandwidth.
To avoid dropping frames on congested ports, the switch provides 4 Mbits for frame buffering. This
buffer can queue packets awaiting transmission on congested networks.
Spanning Tree
Algorithm
The switch supports these spanning tree protocols:
• Spanning Tree Protocol (STP, IEEE 802.1D) – This protocol provides loop detection. When there
are multiple physical paths between segments, this protocol will choose a single path and
disable all others to ensure that only one route exists between any two stations on the network.
This prevents the creation of network loops. However, if the chosen path should fail for any
reason, an alternate path will be activated to maintain the connection.
• Rapid Spanning Tree Protocol (RSTP, IEEE 802.1w) – This protocol reduces the convergence
time for network topology changes to about 3 to 5 seconds, compared to 30 seconds or more
for the older IEEE 802.1D STP standard. It is intended as a complete replacement for STP, but
can still interoperate with switches running the older standard by automatically reconfiguring
ports to STP-compliant mode if they detect STP protocol messages from attached devices.
• Multiple Spanning Tree Protocol (MSTP, IEEE 802.1s) – This protocol is a direct extension of
RSTP. It can provide an independent spanning tree for different VLANs. It simplifies network
management, provides for even faster convergence than RSTP by limiting the size of each
region, and prevents VLAN members from being segmented from the rest of the group (as
sometimes occurs with IEEE 802.1D STP).
Connectivity
Fault
Management
The switch provides connectivity fault monitoring for end-to-end connections within a designated
service area by using continuity check messages which can detect faults in maintenance points,
fault verification through loop back messages, and fault isolation with link trace messages.
Virtual LANs The switch supports up to 4093 VLANs. A Virtual LAN is a collection of network nodes that share
the same collision domain regardless of their physical location or connection point in the network.
The switch supports tagged VLANs based on the IEEE 802.1Q standard. Members of VLAN groups
can be dynamically learned via GVRP, or ports can be manually assigned to a specific set of VLANs.
This allows the switch to restrict traffic to the VLAN groups to which a user has been assigned. By
segmenting your network into VLANs, you can:
• Eliminate broadcast storms which severely degrade performance in a flat network.
• Simplify network management for node changes/moves by remotely configuring VLAN
membership for any port, rather than having to manually change the network connection.
• Provide data security by restricting all traffic to the originating VLAN, except where a
connection is explicitly defined via the switch's routing service.