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Property | Description |
|---|---|
| Bandwith Limit: | This allows you to manually set the bandwidth limit for the CAKE shaper. For instance, if you're aware that your ISP provides you with a 100Mbps connection, you could set the rate to 100Mbps to prevent CAKE from trying to use more bandwidth than available. |
| Autorate Ingress | This is useful in situations where the connection quality varies. For example, if you're on a cellular data connection which that can fluctuate wildly based on signal strength, this option allows CAKE to adjust the shaper bandwidth dynamically to match the estimated capacity of the link. |
| Overhead | The overhead parameter in the CAKE queue discipline allows you to specify the per-packet overhead (in bytes) to account for when shaping traffic. This is particularly important when dealing with technologies such as DSL, where protocol encapsulation adds additional bytes to each packet. Accurately accounting for these overheads will lead to more precise control of the actual bandwidth being used. |
| MPU | The Minimum Packet Unit (MPU) parameter allows you to round up the size of each packet to a specified minimum. This is useful for link layer technologies that have a minimum packet size. For example, if your link layer technology has a minimum packet size of 64 bytes, you can configure CAKE with mpu 64. |
| ATM | This is for Asynchronous Transfer Mode, a type of network technology often used in DSL broadband connections. ATM uses fixed 53-byte cells, each of which can carry 48 bytes of payload. The atm keyword compensates for this overhead. |
| Overhead Scheme | The overhead compensation feature in CAKE allows it to account for the extra bytes added by various link layer technologies, which can be significant in some cases. This is important because CAKE operates on the packet sizes reported by the Linux kernel, which do not include these extra bytes. If the overhead is not accounted for, CAKE's shaper might allow more data onto the link than it can actually handle, leading to unexpected packet loss. |
| RTT | Manually specify an RTT. This is for advanced users who know the exact RTT they want to use. |
| RTT Scheme | The CAKE queue discipline allows you to specify the Round Trip Time (RTT) it should consider when managing traffic. This is important because the time it takes for a packet to travel from a source to a destination and back impacts how CAKE manages network congestion. If the actual RTT of your network is close to the value you specify, both the throughput and latency of your network should be well managed. |
| Diffserv | Diffserv (Differentiated Services) is a mechanism used to prioritize and classify network traffic based on the Diffserv field in the IP packet header. CAKE (Common Applications Kept Enhanced) provides Diffserv support, allowing traffic to be divided into "tins" (traffic classes) and applying different treatment to each tin. |
| Flow Mode | When flow isolation is enabled, CAKE puts packets from different flows into different queues. Each queue maintains its own Active Queue Management (AQM) state, and packets are delivered from each queue fairly using a DRR++ (Deficit Round Robin++) algorithm. This algorithm works to minimize latency for "sparse" flows, or flows that contain fewer packets. |
| ACK Filter | ACK or acknowledgement acknowledgment filters are a feature of the Cake algorithm that allows for the handling of TCP ACK (acknowledgment) packets. TCP ACK packets are essential to the function of the TCP protocol; they acknowledge the receipt of TCP segments, providing a form of flow control. However, these packets can consume a significant portion of your upload bandwidth, especially when downloading large files. By implementing ACK filtering, Cake can compress these ACKs, reducing their impact on upload bandwidth. |
| NAT | These options control how CAKE handles traffic when Network Address Translation (NAT) is being used. |
| Wash | The "wash" option in the CAKE queue discipline is used to address the issue of frequently mis-marked traffic entering or exiting a DiffServ (Differentiated Services) domain. When traffic passes through networks or providers, there is a chance that the DSCP (Differentiated Services Code Point) markings could be modified or incorrectly assigned. |
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- flowblind - This parameter disables flow isolation, and all traffic goes through a single queue for each 'tin' or traffic class. Useful in scenarios where specific flow isolation is not needed or desired, such as when you want to process all traffic the same way regardless of source or destination.
- srchost - Here, flows are determined solely by the source address. This could be beneficial on the outgoing path of an Internet Service Provider (ISP) backhaul. A telecom company might use this to ensure fair use of its backbone network by different regions or customers.
- dsthost - With this parameter, flows are characterized only by their destination address. This might be beneficial on the incoming path of an ISP backhaul. An enterprise could use this to balance incoming traffic to its different servers.
- hosts - In this case, flows are defined by source-destination host pairs. This is host isolation rather than flow isolation. This might be useful in a data center network, where you want to ensure that communication between specific pairs of servers is fair.
- flows - Flows are characterized by the entire 5-tuple: source address, destination address, transport protocol, source port, and destination port. This is the kind of flow isolation performed by SFQ and fq_codel. This could be used by a cloud provider to ensure fairness among different virtual machines communicating over various protocols and ports.
- dual-srchost - Here, flows are defined by the 5-tuple, and fairness is applied first over source addresses, then over individual flows. This is a good choice for outgoing traffic from a Local Area Network (LAN) to the internetInternet. A university might use this to prevent any single user or device from hogging the internet connection, no matter how many different connections they're using.
- dual-dsthost - In this case, flows are defined by the 5-tuple, and fairness is applied first over destination addresses, then over individual flows. This is suitable for incoming traffic to a LAN from the internet. A large company could use this to prevent any single server or system from overwhelming the network's incoming bandwidth.
- triple-isolate - This is the default setting where flows are defined by the 5-tuple. Fairness is applied over both source and destination addresses intelligently, as well as over individual flows. This prevents any one host on either side of the link from monopolizing it with a large number of flows. A Internet Service Provider (ISP) might use this to ensure fair service to all its customers, regardless of how many connections they have and whether they
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- ack-filter - This enables the ACK filter feature. With this option, Cake will attempt to identify and filter out ACK packets that are do not conveying convey significant new information or do not need to be sent immediately, helping to improve the utilization of the upload bandwidth.
- ack-filter-aggressive - This is a more aggressive version of the ack-filter option. It will result in more ACK packets being compressed or filtered out, which can lead to further improvements in upload bandwidth utilization but may potentially impact TCP performance.The use of the ack-filter or ack-filter-aggressive options depends on your specific network conditions and requirements. For instance, if you find that ACK packets are using a large portion of your available upload bandwidth, then enabling the ACK filter might help. On the other hand, if you're experiencing issues with TCP performance and suspect that ACK filtering might be contributing, you could try disabling it or using the less aggressive option.
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