Cisco WS-C2955C-12 - Syst. 2955 Switch Specifications download pdf (Page 9)

Cisco Systems, Inc.

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Other default feature details for the Cisco Catalyst 2955 Switch include:

• Management VLAN is VLAN1

• VLAN Membership-Static access ports are in VLAN1

• VTP Management-VTP server mode

• Autonegotiation of port speed and duplex settings

How does IGMP snooping operate in Cisco Catalyst 2955 switches?

IGMP snooping in the Cisco Catalyst 2955 resolves the typical undesirable behavior of a Layer 2 switch that

ﬂoods multicast packets to all ports in the ingress VLAN. Instead, the Cisco Catalyst 2955 snoops for incoming

IGMP requests and decides where the IP multicast members reside. Based on the multicast group membership

information from the IGMP packet, the Cisco Catalyst 2955 sets up a forwarding table for that speciﬁc multicast

group’s trafﬁc. This setup allows the Cisco Catalyst 2955 to forward the IP multicast trafﬁc of a speciﬁc group to

only the ports that have active members of the group.

What is multicast VLAN registration (MVR) and how does it relate to an IP multicast implementation?

In multi-VLAN networks, subscribers to a multicast group may exist in more than one VLAN. Because of the

VLAN boundary restrictions in a network that consists of Layer 2 switches, it may be necessary to replicate the

multicast data transmission to the same group in different VLANs, even if they are on the same physical network.

This results in more bandwidth being consumed than is required for a single data stream to a group. MVR alleviates

this problem by registering a common VLAN for the source and receivers of the multicast data. MVR deﬁnes two

types of ports—source ports and receiver ports. Source ports are ports where the multicast data source is connected,

andreceiverports are portswheresubscribersare connected. MVR treatsbothofthese types of portsasifthey belong

to the same VLAN for switching multicast stream for conﬁgured multicast address.

Is IGMPv3 supported on the Cisco Catalyst 2955?

Yes.

What is 802.1x and how can I implement it in my network?

802.1x is an IEEE standard that deﬁnes how devices should be authenticated when they are attached to LAN

ports. In order to implement 802.1x, a RADIUS authentication server such as Cisco ACS Version 3.0 is needed.

I have the existing Cisco Catalyst 2900 XL and 3500 XL switches that support Cisco Group Management

Protocol. Will these devices interoperate with Cisco Catalyst 2955 switches, which support IGMP snooping?

Yes. The Cisco Catalyst 2955, which supports IGMP snooping, will fully interoperate with your existing

Cisco Catalyst 2900 XL and 3500 XL products that support Cisco Group Management Protocol.

What is the maximum number of multicast entries or groups allowed per Cisco Catalyst 2955 Switch?

The Cisco Catalyst 2955 switches support a maximum of 255 IP multicast groups and support both IGMPv1

and IGMPv2.

What does the mrouter option under IGMP snooping do?

Multicast-capable router ports are added to the forwarding table for every IP multicast entry. The switch learns

of such ports through one of these methods:

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Cisco WS-C2955C-12 - Syst. 2955 Switch Specifications Page 9