Purpose of TDM over Packet technology

Telecom companies and enterprise users can save significant network and equipment costs and generate additional revenue by offering different types of services over a single packet-switched infrastructure by the use of E1oP equipment. The E1oP equipment is also suitable for connecting to Ethernet/packet wireless equipment to achieve fast deployment of E1 services over wireless Ethernet networks. One particular application is to build E1 links with low-cost wireless LAN bridges, replacing expensive TDM/E1 microwave radios. The 2 x E1 over Ethernet (VCL-E1oP) multiplexer may be used to provide legacy TDM services over Ethernet optical fiber or wireless Ethernet/IP networks.

How does the TDM over Packet (2 E1 Port FE Version) equipment work?

The E1 data streams received on the E1 interfaces are converted by the E1oP engine of the E1oP equipment to Ethernet data packets (of a fixed size) and transported over the Ethernet network with UDP/IP, MEF, or MPLS headers. At the receiving end, the E1oP reconstructs the original data streams by removing the IP, MEF, or MPLS headers and converts the Ethernet data packets back to E1 frames using a highly reliable and accurate clock recovery mechanism. The 'VCL-E1oP' (2 E1 Port FE Version) offers the user a choice of standard E1-to-packet and packet-to-E1 conversion mechanisms that include SAToP and CESoPSN technologies.

E1 and E1oP Interface

• Supports 2 independent E1 interfaces
• Circuit emulation platform that migrates existing TDM-based legacy services to a next-generation network.
• Supported standard TDM over IP RFCs:
• RFC 5086 - Structure-Aware Time Division Multiplexed (TDM) Circuit Emulation Service over Packet Switched Network (CESoPSN) (12/2007)
• RFC 5087 - Time Division Multiplexing over IP (TDMoIP) (12/2007)
• RFC 4553 - Structure-Agnostic Time Division Multiplexing (TDM) over Packet (SAToP) (06/2006)
• Clock options: Internal, External, Adaptive, Recovered Clock, and Asymmetrical (One-Clock and Two-Clock) options for the E1 TDM port synchronization. Automatic clock priority selection with fallback
• Supports CESoPSN payload mechanism to support the fractional E1 with data rate of 64 Kbps to 2.048 Mbps (DS0 timeslot level). User-configurable data rate from 64 kbps to 2048 kbps, in steps of 64 kbps
• The CESoPSN payload mechanism feature allows the user to optimize the packet-switched network by limiting its usage to the corresponding number of time slots carried by an E1 channel.
• Supports SAToP payload mechanism to transport full E1 (transparent to the structure of the TDM frame, useful for transporting framed/unframed E1 channels)
• Supports IETF-PWE3 (pseudo-wire) transport mechanism
• Supports IP, MPLS, and MEF8 (Metro-Ethernet) tagging
• Supports three E1 framing modes—framed, unframed, and multi-framed with CAS signaling
• Supports network latency/packet delay variation/jitter buffer of up to 512 ms
• Absolute and differential timestamps
• Jitter and Wander conforms to G.823/G.824 and G.8261 and TDM specifications.
• 120 ohms balanced E1 interfaces. Optional 75-ohm BNC interface (120-ohm to 75-ohm cables provided)
• E1 local and remote loop-back (RLOOP) facility for testing and diagnostics.

Ethernet/IP Network Interface

• Optical SFP-based (100Base-FX), electrical (10/100Base-T), and PoE electrical (10/100Base-T) Ethernet port options.
• 4 x 10/100BaseT Copper Ports.
• 2 x 10/100BaseT Copper Ports, 2 x 10/100BaseT Ports with PoE.
• 2 x 100BaseFX optical fiber ports, 2 x 10/100BaseT copper ports.
• 2 x 100BaseFX optical fiber ports, 2 x 10/100BaseT ports with PoE. (may use any one combination of the above-mentioned Ethernet ports)
• Power over Ethernet (PoE) (available options as above). Meets and exceeds the Telcordia GR-1089-CORE Lighting and Power Contact Protection requirements.
• Point-to-point and point-to-multipoint applications based on IP addressing.
• Supports drop and insert applications.
• 1+1 Ethernet Link Redundancy/Redundant Link Protection.
• Supports QoS, 802.1q, and 802.1p-based packet priority.
• Q-in-Q Tagging.
• Flow control in an Ethernet packet networks: (regulating traffic)
• Port/customer-based bandwidth allocation (port rate limiting—ingress and egress)
• DSCP and 802.1Q/802.1p-based packet tagging and prioritization
• MPLS, MEF, and UDP tagging for Ethernet traffic.
• Separate IP address for TDM traffic and equipment management
• VLAN tagging for TDM traffic and equipment access/management
• User-configurable MTU (E1oP payload) packet size up to 1500 bytes.
• 802.1Q tag-based VLANs support 1-4095 VLAN IDs.
• Supports packet priority assignment (IP diffserv/DSCP).

Few Key Features Explained

The VLAN-based priority (classifying services)—The VLAN-based priority feature allows the user to assign priorities to different VLANs carrying various types of services/traffic according to user categories and preferences. The user may assign the highest priority to TDM (E1/E3) traffic and Ethernet services on a lower priority. Users may also configure which TDM link should be given preference over the other TDM links when the uplink bandwidth falls below a particular threshold.

Flow Control in an Ethernet Packet Network: (Regulating Traffic)—The flow control feature allows the user to regulate Ethernet traffic flow to minimize packet loss due to data bursts.

Port/Customer-based Bandwidth Allocation (Port Rate Limiting)—Port-based ingress Ethernet rate limiting allows the user to assign the bandwidth as per port/service requirements, in addition to provisioning traffic by using 802.1Q and 802.1p VLANs and packet priority.

System Management, Monitoring, and Alarm Interfaces

• External Alarm—Dry contact relay alarms are also available at the rear of the system to connect the system to an external alarm.
• NMS (Network Management System) to monitor multiple units from a single central location.
• Supports system temperature monitoring with high-temperature threshold and low-temperature threshold alarms and SNMP Traps.
• Supports SNMP V2 monitoring and traps.
• Self-test for checking system errors upon system boot-up.
• Event Logging.
• Clock Performance Alarms.
• Network Performance Alarms.
• Network Performance Monitoring and Diagnostics.
• Online/remote upgrade of firmware.