The ASAP adapter card supports ATM, inverse multiplexing over ATM (IMA), TDM and MLPPP. The Ethernet adapter card has six ports of auto-sensing 10/100 Base-T ports plus two further ports supporting 10/100/1000 Base TX with small form factor pluggable (SFPs) optics. Each slot is connected to the switching fabric on the CSM via a 1 Gb/s link to host existing and future interface types.
Service aggregation and networking
To provide the most efficient transport solution, the Alcatel-Lucent 7705 SAR employs pseudowire encapsulation (PWE3) methods to map services end to end. The use of pseudowires ensures that the key attributes of the service are maintained, while using a cost- effective packet environment to aggregate services.
The Alcatel-Lucent 7705 SAR supports RFC 5086 — Structure-Aware Time Division Multiplexed (TDM) Circuit Emulation Service over Packet Switched Network (CESoPSN) for the encapsu lation and transport of TDM traffic, for example, 2G TDM services. The use of circuit emulation service (CES) ensures that only the active timeslots are transported, keeping bandwidth usage to a minimum. The Alcatel-Lucent 7705 SAR also supports RFC 4717 — Encapsu lation Methods for Transport of
Asynchronous Transfer Mode (ATM) over MPLS Networks (also known as draft-ietf-pwe3-atm-encap). The Alcatel-Lucent 7705 SAR supports N:1 cell mode for transport of ATM-based services. Multiple access ATM ports are bundled together to attain higher speeds using IMA. The IMA protocol is terminated on the Alcatel-Lucent 7705 SAR and only the cells containing user data belonging to a virtual circuit/virtual path (VC/VP) structure are transported.
In addition, the Alcatel-Lucent 7705 SAR supports RFC 4448 — Encapsu lation Methods for Transport of Ethernet over MPLS Networks, which specifies how Ethernet pseudowires can be used to transport Ethernet traffic across the packet network. To offer greater scalability, all the traffic out of an Ethernet port can be carried over a single Ethernet pseudowire or, alternatively, a pseudowire can be created for each VLAN that is assigned to a different service or end-customer. When dynamic signaling is deployed, the end-to-end pseudowire is estab- lished using targeted label distribution protocol (T-LDP) and the MPLS tunnel via LDP. In addition to efficient LDP-based dynamic signaling, static provisioning of both the MPLS tunnel and the pseudowire is also supported.
Quality of service and traffic management
It is critical to maintain the end-to-end quality of service (QoS) for packet traffic. Not all types of traffic have the same set of requirements. Voice traffic in particular requires low latency and jitter (latency variation) and also low loss, whereas data traffic often has less stringent delay requirements but may be very sensitive to loss, as packet loss can seriously constrain applica tion throughput. To offer the req uired treatment throughout the network, traffic flows with different requirements are identified at the access and marked in-line with the appropriate QoS metrics. Traffic classification and marking is carried out based on the following:
Classification (Layer 1/Layer 2/Layer
2.5and/or Layer 3 header):
• Timeslot/port
• Ethernet port/VLAN
•ATM service category
(CBR/rt-VBR/nrt-VBR/UBR)
•ATM VC
•Ethernet 802.1p/VLAN
•IP DSCP/MPLS EXP
Marking:
•Layer 2 (802.1p)
•Layer 2.5 (EXP) both for tunnel and PWE3
•Layer 3 (DiffServ)
Figure 1. Low-cost, high-quality backhaul using MPLS pseudowires
Cell Site
BTS | TDM | |
| |
| ATM | 7705 |
Node B | |
| SAR |
| Ethernet |
| |
Telemetry | | |
| | MTSO | |
| | TDM | |
PSN/Metro Ethernet/ | Ethernet, MLPPP | ATM | BSC |
SONET/SDH | | Ethernet | |
| | |
| | 7710/7750 SR, | RNC |
| | 7670 RSP |
TDM Pseudowire
MPLS Tunnel | ATM Pseudowire |
Ethernet Pseudowire
MPLS Pseudowires Allow Convergence and Dynamic Bandwidth Allocation
Over Multiple Media, Enabling Low Cost Backhaul
2 Alcatel-Lucent 7705 SAR Data Sheet
