ULA macro in the policy table Re: -06 candidate

[Arifumi Matsumoto <[e-mail]>]

Mark,
thank you for your comment.

As you mention it, it should be less harmful to give the whole ULA
block a lower precedence value, if we assume ULA leakages will happen
here and there by DNS mis-configurations, address information exchange
in P2P applications, and so on.

Regarding communication between ULAs, such a network that really wants
to make use of multiple ULA blocks should have a way of controlling
address selection behavior of their hosts, such as policy table
configuration and DNS configuration.

The question is whether we can accept the appearance of macro in
the policy table.

         Prefix        Precedence Label
         ::1/128               60     0
         <YOUR ULA>:/48        50     1
         ::/0                  40     2
         ::ffff:0:0/96         30     3
         2002::/16             20     4
         2001::/32             10     5
         fc00::/7               5     6
         ::/96                  1    10
         fec0::/10              1    11
         3ffe::/16              1    12

    I assume the line of <YOUR ULA> will be interpreted as a line
    or lines of ULA prefix(es) that is attached to interface(s).

Another point is that a host has to maintain the ULA line in responses
to addition and deletion of the addresses.

Regards,

On 2012/01/18, at 7:26, Mark Andrews wrote:

> 
> ULA need to be de-preferenced except for the local ULA prefixes.
> 
> Below is what I use in FreeBSD 8.  It keeps local traffic using
> fd92:7065:b8e::/48 rather than using the PA address.  If you learn
> a ULA destination address that is not local YOU DO NOT WANT TO USE
> IT by default when you have another choice.
> 
> What you do want is for a interface when it learns a ULA address
> to add the corresponding /48 prefix with a given precedence and a
> unique label to the table if the prefix does not exist.  And
> appropriate cleaning be done when no more interfaces exist in the
> /48.  This may require a manual tag on table entries.
> 
> Mark
> 
>>  more /etc/ip6addrctl.conf 
> #Prefix                          Prec Label     
> ::1/128                           50     0
> ::/0                              40     1     
> 2002::/16                         30     2        
> ::/96                             20     3        
> ::ffff:0.0.0.0/96                 35     4        
> fd92:7065:b8e::/48                45     5 
> fc00::/7                          5      6
>> ifconfig nfe0 inet6
> nfe0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
> 	options=82008<VLAN_MTU,WOL_MAGIC,LINKSTATE>
> 	inet6 fe80::218:f3ff:feba:9a37%nfe0 prefixlen 64 scopeid 0x5 
> 	inet6 fd92:7065:b8e:0:218:f3ff:feba:9a37 prefixlen 64 autoconf 
> 	inet6 2001:470:1f00:820:218:f3ff:feba:9a37 prefixlen 64 autoconf 
>> 
> -- 
> Mark Andrews, ISC
> 1 Seymour St., Dundas Valley, NSW 2117, Australia
> PHONE: [phone]                 INTERNET: [e-mail]


--
Arifumi Matsumoto
  NGN System Architecture Project
  NTT Service Integration Laboratories
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