This guide provides the necessary details for configuring your own router for Capti’s Ethernet Access (EA) services, covering traffic shaping, burst sizes, Multicast/Broadcast traffic, MAC address limits, and additional key configurations.
1. Classes of Service (CoS) Overview
Capti offers two primary Classes of Service (CoS) for Ethernet Access:
- Standard CoS: A best-effort service with a 0:1 CIR to PIR ratio. There is no guaranteed Committed Information Rate (CIR), and all traffic is treated as excess traffic.
- Premium CoS: Guarantees performance with a 1:1 CIR to PIR ratio. This CoS is ideal for time-sensitive applications such as voice, video conferencing, and real-time systems that require guaranteed bandwidth and low latency.
2. Traffic Shaping and Policing
Traffic shaping ensures that packets are transmitted at a controlled rate to avoid congestion and excessive packet drops. It is important to implement shaping on the egress (outbound) traffic of your router to match the service profile.
- Policing: Traffic exceeding the CIR or PIR may be dropped at the network edge, particularly in cases where the service is oversubscribed. This applies to both unicast and multicast/broadcast traffic.
- Shaping: Ensures that excess traffic is delayed (buffered) and transmitted smoothly to match the service bandwidth, preventing packet loss.
Key Requirements for Traffic Shaping:
- Apply traffic shaping per VLAN or sub-interface when using multiple Ethernet Virtual Circuits (EVCs) on a single User Network Interface (UNI).
- Ensure the CIR, PIR, Committed Burst Size (CBS), and Excess Burst Size (EBS) are correctly configured as per the bandwidth profile of your service.
3. Traffic Shaping and Burst Configuration Tables
For Standard CoS (Best-Effort Traffic), all traffic is treated as excess. This means the Committed Information Rate (CIR) is set to zero, and the service operates on a best-effort basis with an Excess Information Rate (EIR) that is fully burstable.
| PIR (Mbps) | CIR Ratio | CIR (Mbps) | CBS (kBytes) | EIR (Mbps) | EBS (kBytes) |
|---|---|---|---|---|---|
| 0.512 | 0:1 | 0 | 1 | 0.512 | 8 |
| 1.024 | 0:1 | 0 | 2 | 1.024 | 16 |
| 2.048 | 0:1 | 0 | 4 | 2.048 | 32 |
| 4.096 | 0:1 | 0 | 8 | 4.096 | 64 |
| 6 | 0:1 | 0 | 12 | 6 | 96 |
| 10 | 0:1 | 0 | 20 | 10 | 160 |
| 20 | 0:1 | 0 | 40 | 20 | 320 |
| 50 | 0:1 | 0 | 80 | 50 | 640 |
| 100 | 0:1 | 0 | 175 | 100 | 1400 |
| 500 | 0:1 | 0 | 850 | 500 | 6800 |
| 1000 | 0:1 | 0 | 1030 | 1000 | 8240 |
For Premium CoS (Guaranteed Performance), the CIR and PIR are matched (1:1 ratio), ensuring guaranteed performance for critical applications such as voice and video services.
| PIR (Mbps) | CIR Ratio | CIR (Mbps) | CBS (kBytes) | EIR (Mbps) | EBS (kBytes) |
|---|---|---|---|---|---|
| 0.512 | 1:1 | 0.512 | 0.627 | 0 | 0 |
| 1.024 | 1:1 | 1.024 | 1.225 | 0 | 0 |
| 2.048 | 1:1 | 2.048 | 2.45 | 0 | 0 |
| 4.096 | 1:1 | 4.096 | 3.675 | 0 | 0 |
| 10 | 1:1 | 10 | 13 | 0 | 0 |
| 50 | 1:1 | 50 | 63 | 0 | 0 |
| 100 | 1:1 | 100 | 125 | 0 | 0 |
| 200 | 1:1 | 200 | 250 | 0 | 0 |
| 1000 | 1:1 | 1000 | 1030 | 0 | 0 |
| 2000 | 1:1 | 2000 | 1030 | 0 | 0 |
4. Maximum Transmission Unit (MTU) Settings
The MTU defines the maximum frame size that can be transmitted through the network. Customers must configure their routers based on the access type:
- Fibre Access: Supports both 1596 bytes and 9000 bytes MTU, allowing the use of jumbo frames for more efficient data transfers.
- Copper Access: The maximum MTU is 1518 bytes. Services that traverse both copper and fibre will be limited to this MTU.
- Mobile Backup: Jumbo frames (9000 bytes) are not supported.
5. MAC Address Limits
There is a 50 MAC address limit per Ethernet Virtual Circuit (EVC). Customers exceeding this limit will encounter connectivity issues, as additional MAC addresses will not be supported. This is particularly important for customers using shared or multi-tenant environments.
6. Multicast and Broadcast Traffic Considerations
Multicast and broadcast traffic is conditionally supported within both the Telstra and Capti networks, but it is subject to the same policing mechanisms as unicast traffic. Excess multicast and broadcast traffic may be dropped if it exceeds the service's CIR or PIR, which could impact performance.
7. Maximum EVCs per Network Termination Unit (NTU)
Depending on the NTU model, there are practical limits on the number of EVCs supported. These limits vary based on the access technology (e.g., copper, fibre). If a customer requires more EVCs than allowed by the NTU, a new NTU installation will be required.
8. Failover to Mobile Backup
If mobile backup is configured, customers must reconfigure their router’s shaping to match the bandwidth profile of the backup service. The same bandwidth profiles (CIR, PIR, CBS, and EBS) that apply to fibre services are used for mobile failover.
Conclusion
Capti offers Managed Routers as part of our service, ensuring proper configuration and optimal performance. However, if you require engineering support for configuring your BYO router, this service is chargeable and provided on a best-effort basis.
For further technical documentation on shaping, please contact your Account Manager to obtain a copy of the TSIS.