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Beginner

Ipn6 ND between routers

25-01-2020-IPv6-Topology.png

 

1.IPv6 ND between vIOS1 & vIOS2.

2.  I understand the whole ND of IPv6 but there is NA  in seq 116 which is for LLA and it generation is causing me trouble.

3. Post  MLD and DAD for LLA,seq 116, unsolicited NA went out from vIOS -1 with target address set to its own LLA. Any reason for such NA  and what triggers a unsolicited NA ?

4. NS frequency timer in set in RA ( re-transmit timer) , if re-transmit timer is set as 0, does it mean NA is always goes out in response to NS ?

 

Note:

Cannot attach pcap file so sharing screen shot below:

 

 

25-01-2020-IPv6-116.png

 

25-01-2020-IPv6-116_expand.png

 

 

1 ACCEPTED SOLUTION

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Cisco Employee

Re: Ipn6 ND between routers

3) After confirming that it can use FE80::1, via the DAD (NS for its own LLA), IOS does unsolicited NA.

 

4) RFC4861 section 4.2 says the following about the retransmission timer:

 

Retrans Timer  32-bit unsigned integer.  The time, in
                     milliseconds, between retransmitted Neighbor
                     Solicitation messages.  Used by address resolution
                     and the Neighbor Unreachability Detection algorithm
                     (see Sections 7.2 and 7.3).  A value of zero means
                     unspecified (by this router).

 

A value of 0 would therefore mean unspecified. Unreachability detection is not really used anymore.

 

Regards, 

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

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1 REPLY 1
Highlighted
Cisco Employee

Re: Ipn6 ND between routers

3) After confirming that it can use FE80::1, via the DAD (NS for its own LLA), IOS does unsolicited NA.

 

4) RFC4861 section 4.2 says the following about the retransmission timer:

 

Retrans Timer  32-bit unsigned integer.  The time, in
                     milliseconds, between retransmitted Neighbor
                     Solicitation messages.  Used by address resolution
                     and the Neighbor Unreachability Detection algorithm
                     (see Sections 7.2 and 7.3).  A value of zero means
                     unspecified (by this router).

 

A value of 0 would therefore mean unspecified. Unreachability detection is not really used anymore.

 

Regards, 

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

View solution in original post

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