Cisco Sg3008 Manual

							VLAN Management
Access Port Multicast TV VLAN
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Configuration
Work flow
Configure TV VLAN with the following steps:
1. Define a TV VLAN by associating a Multicast group to a VLAN (using the 
Multicast Group to VLAN page).
2. Specify the access ports in each Multicast VLAN (using the Port Multicast VLAN 
Membership page. 
Multicast T V Group to VLAN
To define the Multicast TV VLAN configuration:
STEP 1Click VLAN Management > Access Port Multicast TV VLAN > Multicast Group to 
VLAN.
The following fields are displayed:
•Multicast Group—IP address of the Multicast group. 
•Multicast TV VLAN—VLAN to which the Multicast packets are assigned.
STEP  2Click Add to associate a Multicast group to a VLAN. Any VLAN can be selected. 
When a VLAN is selected, it becomes a Multicast TV VLAN. Group registration All Multicast group 
registration is dynamic.Groups must be associated 
to Multicast VLAN statically, 
but actual registration of 
station is dynamic.
Receiver ports VLAN can be used to 
both send and receive 
traffic (both Multicast and 
Unicast).Multicast VLAN can only be 
used to receive traffic by the 
stations on the port (only 
Multicast).
Security and 
IsolationReceivers of same 
multicast stream are on 
the same data VLAN and 
can communicate with 
each otherReceivers of same multicast 
stream are in different 
Access VLANs and isolated 
from each other  Regular VLAN Multicast T V VLAN 
						

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Customer Port Multicast TV VL AN
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STEP  3Click Apply. Multicast TV VLAN settings are modified, and written to the Running 
Configuration file.
Port Multicast VLAN Membership
To define the Multicast TV VLAN configuration:
STEP 1Click VLAN Management > Access Port Multicast TV VLAN > Port Multicast VLAN 
Membership.
STEP  2Select a VLAN from the Multicast TV VLAN field.
STEP  3The Candidate Access Ports list contains all access ports configured on the 
device. Move the required ports from the Candidate Access Ports field to the 
Member Access Ports field.
STEP  4Click Apply. Multicast TV VLAN settings are modified, and written to the Running 
Configuration file.
Customer Port Multicast T V VLAN
A triple play service provisions three broadband services, over a single 
broadband connection:
•High-speed Internet access 
•Vide o
•Vo ic e
The triple play service is provisioned for service provider subscribers, while 
keeping Layer 2-isolation between them.
Each subscriber has a CPE MUX box. The MUX has multiple access ports that are 
connected to the subscribers devices (PC, telephone and so on), and one network 
port that is connected to the access device.
The box forwards the packets from the network port to the subscribers devices 
based on the VLAN tag of the packet. Each VLAN is mapped to one of the MUX 
access ports. 
						

							VLAN Management
Customer Port Multicast TV VL AN
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Packets from subscribers to the service provider network are forwarded as VLAN 
tagged frames, in order to distinguish between the service types, which mean that 
for each service type there is a unique VLAN ID in the CPE box.
All packets from the subscriber to the service provider network are encapsulated 
by the access device with the subscriber ’s VLAN configured as customer VLAN 
(Outer tag or S-VID), except for IGMP snooping messages from the TV receivers, 
which are associated with the Multicast TV VLAN. VOD information that is also 
sent from the TV receivers are sent like any other type of traffic. 
Packets from the service provider network that received on the network port to 
the subscriber are sent on the service provider network as double tag packets, 
while the outer tag (Service Tag or S-Tag) represent one of the two type of VLAN 
as following:
•Subscriber ’s VLAN (Includes Internet and IP Phones) 
•Multicast TV VLAN
The inner VLAN (C-Tag) is the tag that determines the destination in the 
subscriber ’s network (by the CPE MUX).
Work flow
1. Configure an access port as a customer port (using the VLAN Management > 
Interface Settings page). See QinQ for more information.
2. Configure the network port as a trunk or general port with subscriber and 
Multicast TV VLAN as tagged VLANS. (using the VLAN Management > Interface 
Settings page. 
3. Create a Multicast TV VLAN with up to 4094 different VLAN(s). (The VLAN 
creation is done via the regular VLAN management configuration)
4. Associate the customer port to a Multicast TV VLAN, using the Port Multicast 
VLAN Membership page.
5. Map the CPE VLAN (C-TAG) to the Multicast TV VLAN (S-Tag), using the CPE 
VLAN to VLAN page.
Mapping CPE VLANs to Multicast T V VLANs
To support the CPE MUX with subscribers VLANs, subscribers may require 
multiple video providers, and each provider is assigned a different external VLAN.
CPE (internal) Multicast VLANs must be mapped to the Multicast provider 
(external) VLANs.  
						

							VLAN Management
Customer Port Multicast TV VL AN
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After a CPE VLAN is mapped to a Multicast VLAN, it can participate in IGMP 
snooping.
To  m a p  C P E  V L A N s :
STEP 1Click VLAN Management > Customer Port Multicast TV VLAN > CPE VLAN to 
VLAN.
STEP  2Click Add.
STEP  3Enter the following fields:
•CPE VLAN—Enter the VLAN defined on the CPE box.
•Multicast TV VLAN—Select the Multicast TV VLAN which is mapped to the 
CPE VLAN.
STEP  4Click Apply. CPE VLAN Mapping is modified, and written to the Running 
Configuration file.
CPE Port Multicast VLAN Membership
The ports associated with the Multicast VLANs must be configured as customer 
ports (see Configuring VLAN Interface Settings). 
Use the Port Multicast VLAN Membership page to map these ports to Multicast TV 
VLANs as described in Port Multicast VLAN Membership 
						

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Customer Port Multicast TV VL AN
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Spanning Tree
This section describes the Spanning Tree Protocol (STP) (IEEE802.1D and 
IEEE802.1Q) and covers the following topics:
•STP Flavors
•Configuring STP Status and Global Settings
•Defining Spanning Tree Interface Settings
•Configuring Rapid Spanning Tree Settings
•Multiple Spanning Tree
•Defining MSTP Properties
•Mapping VLANs to a MSTP Instance
•Defining MSTP Instance Settings
•Defining MSTP Interface Settings
STP Flavors
STP protects a Layer 2 Broadcast domain from Broadcast storms by selectively 
setting links to standby mode to prevent loops. In standby mode, these links 
temporarily stop transferring user data. After the topology changes so that the 
data transfer is made possible, the links are automatically re-activated.
Loops occur when alternate routes exist between hosts. Loops in an extended 
network can cause switches to forward traffic indefinitely, resulting in increased 
traffic load and reduced network efficiency.
STP provides a tree topology for any arrangement of switches and 
interconnecting links, by creating a unique path between end stations on a 
network, and thereby eliminating loops. 
						

							Spanning Tree
Configuring STP Status and Global Settings
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The device supports the following Spanning Tree Protocol versions:
•Classic STP – Provides a single path between any two end stations, avoiding 
and eliminating loops.
•Rapid STP (RSTP) – Detects network topologies to provide faster 
convergence of the spanning tree. This is most effective when the network 
topology is naturally tree-structured, and therefore faster convergence 
might be possible. RSTP is enabled by default.
•Multiple STP (MSTP) – MSTP is based on RSTP. It detects Layer 2 loops, and 
attempts to mitigate them by preventing the involved port from transmitting 
traffic. Since loops exist on a per-Layer 2-domain basis, a situation can occur 
where there is a loop in VLAN A and no loop in VLAN B. If both VLANs are on 
Port X, and STP wants to mitigate the loop, it stops traffic on the entire port, 
including VLAN B traffic.
MSTP solves this problem by enabling several STP instances, so that it is 
possible to detect and mitigate loops separately in each instance. By 
associating instances to VLANs, each instance is associated with the 
Layer 2 domain on which it performs loop detection and mitigation. This 
enables a port to be stopped in one instance, such as traffic from VLAN A 
that is causing a loop, while traffic can remain active in another domain 
where no loop was seen, such as on VLAN B.
Configuring STP Status and Global Settings
The STP Status and Global Settings page contains parameters for enabling STP, 
RSTP, or MSTP. 
Use the STP Interface Settings page, RSTP Interface Settings page, and MSTP 
Properties page to configure each mode, respectively.
To set the STP status and global settings:
STEP 1Click Spanning Tree > STP Status & Global Settings.
STEP  2Enter the parameters.
Global Settings:
•Spanning Tree State—Enable or disable STP on the device.
•STP Operation Mode—Select an STP mode. 
						

							Spanning Tree
Configuring STP Status and Global Settings
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•BPDU Handling—Select how Bridge Protocol Data Unit (BPDU) packets are 
managed when STP is disabled on the port or the device. BPDUs are used 
to transmit spanning tree information. 
-Filtering—Filters BPDU packets when Spanning Tree is disabled on an 
interface.
-Flooding—Floods BPDU packets when Spanning Tree is disabled on an 
interface.
•Path Cost Default Values—Selects the method used to assign default path 
costs to the STP ports. The default path cost assigned to an interface varies 
according to the selected method.
-Shor t—Specifies the range 1 through 65,535 for port path costs.
-Long—Specifies the range 1 through 200,000,000 for port path costs. 
Bridge Settings:
•Priority—Sets the bridge priority value. After exchanging BPDUs, the device 
with the lowest priority becomes the Root Bridge. In the case that all bridges 
use the same priority, then their MAC addresses are used to determine the 
Root Bridge. The bridge priority value is provided in increments of 4096. For 
example, 4096, 8192, 12288, and so on. 
•Hello Time—Set the inter val (in seconds) that a Root Bridge waits between 
configuration messages. 
•Max Age—Set the interval (in seconds) that the device can wait without 
receiving a configuration message, before attempting to redefine its own 
configuration.
•Forward Delay—Set the interval (in seconds) that a bridge remains in a 
learning state before forwarding packets. For more information, refer to 
Defining Spanning Tree Interface Settings.
Designated Root:
•Bridge ID—The bridge priority concatenated with the MAC address of the 
device.
•Root Bridge ID—The Root Bridge priority concatenated with the MAC 
address of the Root Bridge.
•Root Port—The port that offers the lowest cost path from this bridge to the 
Root Bridge. (This is significant when the bridge is not the root.)
•Root Path Cost—The cost of the path from this bridge to the root. 
						

							Spanning Tree
Defining Spanning Tree Interface Settings
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•Topology Changes Counts—The total number of STP topology changes 
that have occurred.
•Last Topology Change—The time interval that elapsed since the last 
topology change occurred. The time appears in a days/hours/minutes/
seconds format.
STEP  3Click Apply. The STP Global settings are written to the Running Configuration file.
Defining Spanning Tree Interface Settings
The STP Interface Settings page enables you to configure STP on a per-port 
basis, and to view the information learned by the protocol, such as the designated 
bridge.
The defined configuration entered is valid for all flavors of the STP protocol.
To configure STP on an interface:
STEP 1Click Spanning Tree > STP Interface Settings.
STEP  2Select an interface and click Edit.
STEP  3Enter the parameters
•Interface—Select the Port or LAG on which Spanning Tree is configured.
•STP—Enables or disables STP on the port.
•Edge Port—Enables or disables Fast Link on the port. If Fast Link mode is 
enabled on a port, the port is automatically set to   Forwarding state when 
the port link is up. Fast Link optimizes the STP protocol convergence. The 
options are:
-Enable—Enables Fast Link immediately.
-Auto—Enables Fast Link a few seconds after the interface becomes 
active. This allows STP to resolve loops before enabling Fast Link.
-Disable—Disables Fast Link.
NOTEIt is recommended to set the value to Auto so that the device sets 
the por t to fast link mode if a host is connected to it , or sets it as a regular 
STP port if connected to another device. This helps avoid loops.  
						

							Spanning Tree
Defining Spanning Tree Interface Settings
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•Root Guard—Enables or disables Root Guard on the device. The Root 
Guard option provides a way to enforce the root bridge placement in the 
network. 
Root Guard ensures that the port on which this feature is enabled is the 
designated port. Normally, all root bridge ports are designated ports, unless 
two or more ports of the root bridge are connected. If the bridge receives 
superior BPDUs on a Root Guard-enabled port, Root Guard moves this port 
to a root-inconsistent STP state. This root-inconsistent state is effectively 
equal to a listening state. No traffic is forwarded across this port. In this way, 
Root Guard enforces the position of the root bridge. 
•BPDU Guard—Enables or disables the Bridge Protocol Data Unit (BPDU) 
Guard feature on the port. 
The BPDU Guard enables you to enforce the STP domain borders and keep 
the active topology predictable. The devices behind the ports that have 
BPDU Guard enabled cannot influence the STP topology. At the reception of 
BPDUs, the BPDU guard operation disables the port that has BPDU 
configured. In this case, a BPDU message is received, and an appropriate 
SNMP trap is generated.
•BPDU Handling—Select how BPDU packets are managed when STP is 
disabled on the port or the device. BPDUs are used to transmit spanning tree 
information. 
-Use Global Settings—Select to use the settings defined in the STP 
Status and Global Settings page.
-Filtering—Filters BPDU packets when Spanning Tree is disabled on an 
interface.
-Flooding—Floods BPDU packets when Spanning Tree is disabled on an 
interface.
•Path Cost—Set the port contribution to the root path cost or use the default 
cost generated by the system. 
•Priority—Set the priority value of the port. The priority value influences the 
port choice when a bridge has two ports connected in a loop. The priority is 
a value from 0 to 240, set in increments of 16.
•Port State—Displays the current STP state of a port. 
-Disabled—STP is currently disabled on the port. The port forwards 
traffic while learning MAC addresses.