Description

Tahoe 4681 is a four-port card with G.shdsl+ modems for the Tahoe DSLAM concentrator. Functionally it corresponds to the Tahoe 684 modem in a 19" rack-mount version.

Data rate

Each port delivers up to 5.7 Mbps over a distance of several kilometres. The ports can be bonded, up to 22.8 Mbps in a single stream on four pairs.

Features

At the other end of the line there can be four Tahoe 681 modems, two Tahoe 682 or one Tahoe 684. Traffic from the individual ports goes to the shared Ethernet port in a single stream or separated into VLANs: the DSL ports as untagged, the Ethernet port as tagged, with an external switch separating the traffic from the individual lines.

Technical data

Throughput	up to 5.7 Mbps per port up to 22.8 Mbps on a bundled 8-wire line
Standards	G.shdsl, conforms to ITU G.991.2
Interface	Ethernet 10/100 Base-T
Modulation	TCPAM-32 up to 30% higher reach in comparison to HDSL
Features	TCP/IP router NAT/masquerade firewall telnet and SSH management SNMP management serial console management DHCP/BOOTP Server DHCP/BOOTP Relay Agent (relaying of the DHCP/BOOTP requests to a central server) firmware upgrade using TFTP managed or unmanaged bridge functionality logging through syslog 802.1q VLAN support inside temperature measurement automatic traffic balancing among four DSL lines individual throughput settings for each line (in case of quality differences between the lines) automatic fall back to 6-, 4- or 2-wire transmission in case of line failure
Processor	Freescale PowerPC 100MHz
Memory	4MB SDRAM
Performance	up to 15,000 packets per second
Network protocols	TCP, IP, UDP, ICMP, TFTP, SNMP, DHCP, BOOTP, PPP, Frame Relay, HDLC, Cisco® HDLC, IEEE 802.1q
WAN encapsulation	ATM AAL5
Dimensions	30 mm (width) x 128 mm (height) x 185 mm (depth)
Weight	190 g

Reach

Values below were measured on a test line of 0.5mm wire diameter. They depend on an actual line and thus are not guaranteed. They may be different - higher or lower - in an individual case.

Throughput	Reach on 8 wires	Reach on 4 wires	Reach on 2 wires
22784 kbps	2500 m	-	-
16896 kbps	2900 m	-	-
14336 kbps	3200 m	-	-
11392 kbps	3600 m	2500 m	-
6272 kbps	4200 m	3500 m	-
5696 kbps	4700 m	3600 m	2500 m
3072 kbps	5900 m	4100 m	3500 m
2048 kbps	6900 m	5000 m	3900 m
1024 kbps	7500 m	6900 m	5000 m