Document usage of variable "asn" in configuration #71

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2021-07-02T12:13:22+08:00

bluikko commented

2021-07-02 12:13:22 +08:00

(Migrated from github.com)

There are a few issues that refer using the asn = configuration option as a list and then somehow that list of ASNs can be used in large communities.

But I could not figure out how to even use the simple asn = 65534 in communities.

Say, I have:

[server]
...
# In reality I'm testing with a 32-bit ASN
asn = 65534

And then a large community beginning with this ASN:

[bgp_communities]
65534:123:45 = Some community

If I understand correctly, somehow the asn variable could be used in place of the ASN in the community.

I have tested:

asn:123:45 = ...
ASN:123:45 = ...
$asn:123:45 = ...
:123:45 = ...
$ASN:123:45 = ...

None of these work and the large community 65534:123:45 is undetected in Alice-LG.

Am I understanding the purpose of the asn variable correctly? What is the syntax of using it?

This should be documented in my opinion - or an example of usage in the example config file.

Some other points, I'd prefer not to open more issues without feedback if these are valid issues or user errors:

At de-cix Alice-LG instance the communities drop-down list has colorized communities. Is this a feature of Alice-LG or themed or a specific modification at de-cix?
At Alice-LG startup I am seeing Skipping malformed BGP community: but no line is listed as pkg/backend/config.go would indicate. As a test I commented out all 3 community stanza from configuration and then this line was displayed 3 times... could not locate where this error comes from.
With BIRD2 the IPv4 and IPv6 features are merged. This leads to the IPv4 birdwatcher listing all IPv6 neighbors with 0 routes - and conversely the IPv6 birdwatcher instance lists all IPv4 neighbors with 0 routes.

There are a few issues that refer using the `asn =` configuration option as a list and then somehow that list of ASNs can be used in large communities. But I could not figure out how to even use the simple `asn = 65534` in communities. Say, I have: ``` [server] ... # In reality I'm testing with a 32-bit ASN asn = 65534 ``` And then a large community beginning with this ASN: ``` [bgp_communities] 65534:123:45 = Some community ``` If I understand correctly, somehow the `asn` variable could be used in place of the ASN in the community. I have tested: ``` asn:123:45 = ... ASN:123:45 = ... $asn:123:45 = ... :123:45 = ... $ASN:123:45 = ... ``` None of these work and the large community 65534:123:45 is undetected in Alice-LG. Am I understanding the purpose of the `asn` variable correctly? What is the syntax of using it? This should be documented in my opinion - or an example of usage in the example config file. Some other points, I'd prefer not to open more issues without feedback if these are valid issues or user errors: - At de-cix Alice-LG instance the communities drop-down list has colorized communities. Is this a feature of Alice-LG or themed or a specific modification at de-cix? - At Alice-LG startup I am seeing `Skipping malformed BGP community:` but no line is listed as `pkg/backend/config.go` would indicate. As a test I commented out all 3 community stanza from configuration and then this line was displayed 3 times... could not locate where this error comes from. - With BIRD2 the IPv4 and IPv6 features are merged. This leads to the IPv4 birdwatcher listing all IPv6 neighbors with 0 routes - and conversely the IPv6 birdwatcher instance lists all IPv4 neighbors with 0 routes.

annikahannig commented

2021-07-06 00:04:16 +08:00

(Migrated from github.com)

The way this variable is used is a bit unfortunate and has some legacy background. This should be cleaned up to support multiple asns.

annikahannig commented

2021-07-06 00:12:18 +08:00

(Migrated from github.com)

It is not used in the communities.
The communities provide a text mapping with a wildcard and $1, $2, ($3) matching the parts of the community representation: 1234:*:789 = "text $2 $1"
Will be used in the frontend to evalutate the community "1234:56:789" to "text 789 56"

It is not used in the communities. The communities provide a text mapping with a wildcard and $1, $2, ($3) matching the parts of the community representation: 1234:*:789 = "text $2 $1" Will be used in the frontend to evalutate the community "1234:56:789" to "text 789 56"

annikahannig commented

2021-07-06 00:13:36 +08:00

(Migrated from github.com)

With BIRD2 the IPv4 and IPv6 features are merged. This leads to the IPv4 birdwatcher listing all IPv6 neighbors with 0 routes - and conversely the IPv6 birdwatcher instance lists all IPv4 neighbors with 0 routes.

This seems like a bug. Is the configration for single_table or multi_table?

> With BIRD2 the IPv4 and IPv6 features are merged. This leads to the IPv4 birdwatcher listing all IPv6 neighbors with 0 routes - and conversely the IPv6 birdwatcher instance lists all IPv4 neighbors with 0 routes. This seems like a bug. Is the configration for `single_table` or `multi_table`?

bluikko commented

2021-07-06 11:21:22 +08:00

(Migrated from github.com)

It is not used in the communities.
The communities provide a text mapping with a wildcard and $1, $2, ($3) matching the parts of the community representation: 1234:*:789 = "text $2 $1"
Will be used in the frontend to evalutate the community "1234:56:789" to "text 789 56"

Yes I found out about $1 etc, thanks. So I guess I have misunderstood the asn configuration parameter. It is not exactly clear what it is used for then... I myself do not need multiple ASNs.

This seems like a bug. Is the configration for single_table or multi_table?

It is a single table setup.

> It is not used in the communities. > The communities provide a text mapping with a wildcard and $1, $2, ($3) matching the parts of the community representation: 1234:*:789 = "text $2 $1" > Will be used in the frontend to evalutate the community "1234:56:789" to "text 789 56" Yes I found out about `$1` etc, thanks. So I guess I have misunderstood the `asn` configuration parameter. It is not exactly clear what it is used for then... I myself do not need multiple ASNs. > This seems like a bug. Is the configration for single_table or multi_table? It is a single table setup.

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Reference: malhuda/alice-lg#71