Routing paths in Segment Routing

[Van Tong]

Hi all,

I have a small project related to Segment Routing in the university. After implementing segment routing (SR) application in ONOS (v2.1) with Mininet, I found out that there is a difference between the experiments of TCP and UDP.

When I send the TCP packets from a source to a destination, SR application forwards the packets through only one routing path in the normal network condition. However, SR application forwards the UDP packets through some equal-cost multi-paths in the same network condition.

Does anybody know why there is a difference between the experiments of TCP and UDP?

Best regards,

Van

[Yi Tseng]

Hi Van Tong,

It depends on how the ECMP is implemented in the device. Some device uses 5-tuple for hashing and pick the ECMP bucket.

It also depends on how you generate traffic. The device uses 5-tuple hashing usually pick the same path if we use the same header(Eth, IP, Port) for every packet.

Yi

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Open Networking Foundation

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[Van Tong]

Hi Yi,

Thank you very much.

Best regards,

Van

Vào 02:10:06 UTC+1 Thứ Sáu, ngày 08 tháng 11 năm 2019, Yi Tseng đã viết:

Hi Van Tong,

It depends on how the ECMP is implemented in the device. Some device uses 5-tuple for hashing and pick the ECMP bucket.

It also depends on how you generate traffic. The device uses 5-tuple hashing usually pick the same path if we use the same header(Eth, IP, Port) for every packet.

Yi

On Tue, Nov 5, 2019 at 12:52 PM Van Tong <tongva...@gmail.com> wrote:

Hi all,

I have a small project related to Segment Routing in the university. After implementing segment routing (SR) application in ONOS (v2.1) with Mininet, I found out that there is a difference between the experiments of TCP and UDP.

When I send the TCP packets from a source to a destination, SR application forwards the packets through only one routing path in the normal network condition. However, SR application forwards the UDP packets through some equal-cost multi-paths in the same network condition.

Does anybody know why there is a difference between the experiments of TCP and UDP?

Best regards,

Van

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[Van Tong]

Dear Yi,

I have another question related to the update of routing paths in SR application of ONOS.

I want to create the QoS-aware SR, so I modified function getECMPPaths in EcmpShortestPathGraph.java to return the appropriate paths that meet the requirement in term of QoS. Then, I call to the function populateAllRoutingRules in DefaultRoutingHandler.java to repopulate the routing rules.

However, SR keeps the same routing paths when the packets are transmitted from a source to a destination (SR application transmits the packets through a routing path). It means that the routing rules are not yet updated.

Do you know why?

Best regards,

Van

Vào 02:10:06 UTC+1 Thứ Sáu, ngày 08 tháng 11 năm 2019, Yi Tseng đã viết:

Hi Van Tong,

It depends on how the ECMP is implemented in the device. Some device uses 5-tuple for hashing and pick the ECMP bucket.

It also depends on how you generate traffic. The device uses 5-tuple hashing usually pick the same path if we use the same header(Eth, IP, Port) for every packet.

Yi

On Tue, Nov 5, 2019 at 12:52 PM Van Tong <tongva...@gmail.com> wrote:

Hi all,

I have a small project related to Segment Routing in the university. After implementing segment routing (SR) application in ONOS (v2.1) with Mininet, I found out that there is a difference between the experiments of TCP and UDP.

When I send the TCP packets from a source to a destination, SR application forwards the packets through only one routing path in the normal network condition. However, SR application forwards the UDP packets through some equal-cost multi-paths in the same network condition.

Does anybody know why there is a difference between the experiments of TCP and UDP?

Best regards,

Van

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[Yi Tseng]

Hi,

Sorry for the delay.

I am not sure what is the issue here. Where/how did you call the "populateAllRoutingRules" function?

I'd suggest enabling the ONOS debug mode (bazel run onos-local -- clean debug) and attach from the IDE(e.g., IntelliJ) to make sure functions you need is invoked by the app.

Yi

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[Van Tong]

Hi Yi,

I call the populateAllRoutingRules function from SegmentRoutingManager to update the routing paths more frequently.

Do you have any documents explaining the flow graph of the process of the routing paths in SR application of ONOS?

Van

Vào 20:54:57 UTC+1 Thứ Ba, ngày 19 tháng 11 năm 2019, Yi Tseng đã viết:

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[Yi Tseng]

[+Trellis dev mailing list]

I don't have a document that describes the flow.

I'd suggest using debugging mode to find the reason.

Yi

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[Charles Chan]

Route population will generate a lot of debug message that's also useful. You can try to enable them by entering the following in ONOS CLI:
log:set debug org.onosproject.segmentrouting

Thanks,
Charles

[Van Tong]

Hi Charles and Yi,

Thank you very much for the instructions.

Van

Vào 00:12:23 UTC+1 Thứ Năm, ngày 21 tháng 11 năm 2019, Charles Chan đã viết: