Cisco 2921 User Manual

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Cisco 3900 Series, Cisco 2900 Series, and Cisco 1900 Series Integrated Services Routers Generation 2 Software Configuration Guide
Configuring EtherChannel
This chapter describes how to configure EtherChannels on Layer 3 ports on Cisco 1900, 2900, and 3900
Series ISRs. EtherChannel provides fault-tolerant high-speed links between switches, routers, and
servers.
Understanding EtherChannel Feature
EtherChannel allows multiple physical Ethernet links to be combined into one logical link. If a segment
within an EtherChannel fails, traffic previously carried over the failed link switches to the remaining
segments with in the EtherChannel. Thus, EtherChannel provides automatic recovery for the loss of a
link by redistributing the load across the remaining links.
The purpose of the EtherChannel feature is to provide redundancy between ISR and another device and
not to provide scalable bandwidth between them.
Restrictions and Guidelines for EtherChannel Feature
These restrictions and guidelines apply while configuring EtherChannel feature.
• Configure all physical ports in an EtherChannel manually; Negotiation protocol PAgP and LACP
are not supported.
• Each EtherChannel can consists of up to four compatibly configured physical ports. Configuring
more than two EtherChannel per platform is not supported.
• Configure all physical ports in an EtherChannel to work at the same criteria such as speed, duplex,
and trunk mode.
• Each physical port can be a member of one EtherChannel group.
• Assign layer 3 addresses to the port channel logical interface, not to the physical ports in the
channel.
• If trunking is required, make sure IEEE 802.1Q is used. Trunking protocol ISL is not supported.
• After you configure an EtherChannel, the configuration that you apply to the physical ports affects
only the LAN port where you apply the configuration.

Cisco 2921 Specifications

General

Ethernet LAN	Yes
Cabling technology	10/100/1000Base-T(X)
Networking standards	IEEE 802.1Q, IEEE 802.1ag, IEEE 802.3, IEEE 802.3ab, IEEE 802.3af, IEEE 802.3ah, IEEE 802.3u
Ethernet LAN data rates	10, 100, 1000 Mbit/s
Ethernet interface type	Gigabit Ethernet
Product color	Black
Rack capacity	2U
USB version	2.0
RS-232 ports	1
USB ports quantity	2
Ethernet LAN (RJ-45) ports	3
DHCP client	-
Routing protocols	BGP, EIGRP, OSPF
Supported protocols	IPv4, IPv6, IS-IS, IGMPv3, PIM SM, SSM, DVMRP, IPSec, GRE, BVD, MPLS, L2TPv3, PPP, MLPPP, MLFR, HDLC, RS-232, RS-449, X.21, V.35, EIA-530, PPPoE, ATM
Firewall security	Cisco IOS
Operating altitude	0 - 3000 m
Non-operating altitude	0 - 4570 m
Storage temperature (T-T)	-40 - 70 °C
Operating temperature (T-T)	0 - 40 °C
Storage relative humidity (H-H)	5 - 95 %
Operating relative humidity (H-H)	10 - 85 %
AC input voltage	100 - 240 V
Power source type	AC
AC input frequency	47 - 63 Hz
Safety	UL 60950-1, CAN/CSA C22.2 No. 60950-1, EN 60950-1, AS/NZS 60950-1, IEC 60950-1
Electromagnetic compatibility	47 CFR, ICES-003, EN55022, CISPR22, AS/NZS 3548, VCCI V-3, EN 300-386, EN 61000, EN 55024, CISPR 24EN50082-1

Weight and Dimensions

Depth	469.9 mm
Width	438.2 mm
Height	88.9 mm
Weight	13200 g