When setting up Ethernet services with Capti on the Telstra network, it’s crucial to understand the different Class of Service (CoS) options available. CoS allows Telstra to prioritise different types of traffic on their network, ensuring that critical data is delivered quickly and reliably. The CoS levels are designed to support a variety of applications, from VoIP to database queries, depending on the performance requirements.

What is CoS?

CoS, or Class of Service, refers to the level of service quality guaranteed for your internet connection. This impacts how much bandwidth your business can consistently access, especially during high-traffic periods. The right CoS ensures that your connection meets your business’s performance requirements.

Below is a breakdown of the four CoS levels offered by Telstra for Ethernet Access:

1. Expedited Class of Service (CoS)

Expedited CoS is designed for real-time and latency-sensitive traffic. This is the highest level of service offered and is perfect for applications that require ultra-reliable and low-latency data transmission, such as:

  • Voice over IP (VoIP)
  • Video conferencing
  • High-priority real-time applications

With Expedited CoS, data packets are processed first, minimising delays and jitter. This makes it ideal for businesses running mission-critical voice services that cannot tolerate any interruptions. Expedited CoS also offers a high Committed Information Rate (CIR), ensuring a guaranteed minimum bandwidth is available at all times. The Peak Information Rate (PIR) may also be higher during non-congested times, further enhancing performance. Additionally, Telstra provides strict Service Level Agreements (SLAs) for this service, offering guarantees on uptime, low latency, and minimal packet loss.

2. Priority Class of Service (CoS)

Priority CoS is the next tier, optimised for time-sensitive applications that are not as critical as voice, but still require fast, predictable service. Typical use cases include:

  • SQL database queries
  • Real-time financial transactions
  • Data replication

While slightly lower in priority than Expedited, Priority CoS still ensures a high level of performance by allocating more bandwidth and lower latency for these types of data streams. Priority CoS comes with a balanced CIR and PIR, meaning you get a guaranteed minimum bandwidth, with potential for higher speeds during times of low network usage. SLAs for Priority CoS also guarantee solid performance, though they are slightly less stringent compared to Expedited CoS.

3. Premium Class of Service (CoS)

Premium CoS is suited for essential business applications that need reliable delivery but can tolerate some delays. Common use cases include:

  • Email services
  • File transfers
  • Business-critical applications

Premium CoS guarantees better performance than the Standard CoS but is not designed for real-time traffic. It offers a moderate CIR, ensuring that your applications receive a minimum amount of bandwidth. While SLAs for Premium CoS may not be as strict as those for Expedited or Priority, they still provide assurances of solid performance and uptime for most business needs.

4. Standard Class of Service (CoS)

Standard CoS is the basic level of service, suitable for less time-sensitive traffic such as:

  • Internet browsing
  • General data transfers
  • Non-critical applications

While Standard CoS doesn’t guarantee the same level of performance as the higher tiers, it is still a cost-effective solution for traffic that can tolerate occasional delays. CIR for Standard CoS is minimal or non-guaranteed, meaning performance may vary during peak usage periods. However, during low-traffic times, PIR may allow for better-than-expected performance. SLAs for Standard CoS are less strict, reflecting its suitability for non-critical applications.

Understanding Bandwidth and Performance Metrics

When setting up Ethernet services, it’s important to understand how Telstra allocates bandwidth. Two important metrics are Committed Information Rate (CIR) and Peak Information Rate (PIR):

  • CIR (Committed Information Rate): This is the minimum guaranteed bandwidth allocated to your service. Under normal network conditions, Telstra guarantees that the CIR will always be available for your critical applications, regardless of network congestion. It is represented in bits per second (bps). Traffic within the CIR is considered conformant and prioritised for delivery.
  • PIR (Peak Information Rate): PIR represents the maximum possible bandwidth your service can use under optimal conditions, which is the sum of CIR and Excess Information Rate (EIR). If the network is not congested, your service can utilise additional bandwidth beyond the CIR up to the PIR limit. However, any traffic above CIR is considered excess and is not guaranteed, meaning it may be dropped if the network experiences congestion. This allows services to “burst” to higher speeds when there is available capacity .

These metrics help businesses ensure that their network performance meets their operational needs. If you rely on continuous, high-speed connectivity, you’ll want to prioritise CoS levels with higher CIR values.

FAQs: Telstra Ethernet Access Class of Service (CoS)

1. Can I mix different CoS levels in a single connection?

Yes, Telstra allows multiple CoS levels within a single Ethernet Virtual Connection (EVC). This flexibility helps prioritise different types of traffic based on their performance requirements, ensuring critical applications get the bandwidth they need.

2. What happens if my traffic exceeds the bandwidth allocated to a CoS?

If traffic exceeds the allocated bandwidth for a specific CoS, Telstra will apply traffic shaping or policing, meaning lower-priority traffic may be delayed or discarded to ensure higher-priority traffic is unaffected.

3. Which CoS should I choose for general business applications like email and file transfers?

For applications such as email, file transfers, and general business applications, Premium CoS is the recommended choice. It offers a good balance between performance and cost, providing reliable delivery without the need for the highest priority.

4. Can I upgrade my CoS level after my service has been provisioned?

Yes, you can upgrade your CoS level if your business needs change. However, upgrades and changes are subject to your plan, as well as network checks and feasibility, ensuring the requested service adjustments are supported by the existing network infrastructure. 

6. How does Telstra prioritise CoS during network congestion?

During network congestion, Telstra prioritises traffic based on the assigned CoS. Expedited CoS receives the highest priority, followed by Priority, Premium, and finally Standard CoS. This ensures that mission-critical traffic is handled first.

7. Is Standard CoS reliable for everyday browsing and data synchronisation?

Yes, Standard CoS is reliable for everyday internet activities, such as browsing and non-critical data transfers. However, it is not recommended for latency-sensitive or mission-critical applications.

8. Does CoS affect my overall internet speed?

CoS does not change your internet speed but rather prioritises how different types of traffic are handled. Critical traffic like VoIP will get preference over general web browsing during times of congestion, ensuring that your most important applications perform optimally.