|
North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: VoIP over IPsec
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 At 01:24 AM 2/17/2003 -0600, Stephen Sprunk wrote: >Unfortunately, IOS can introduce jitter when encrypting packets. To >mitigate this, you can apply QOS, with a strict priotiy queue for the VoIP >packets and the "qos pre-classify" feature. Your mileage will vary >depending on the CPU power of the router, the traffic levels, and whether >you're using hardware encryption. Stephen, I know this is outside of Charles' original inquiry, but I'm not familiar with this "qos pre-classify" feature. Since we would be encrypting voice traffic ... at what point would you classify it? If I classify it before it goes into the tunnel and gets encrypted, would that classification last once it's encrypted? If we try to classify after it's been encrypted, how can we tell it's voice traffic? It seems to me that jitter from both the actual encryption process as well as that associated with basic serialization would be the potential death of VoIP in this scenario, but I'm not sure mechanisms available to help resolve that risk. -----BEGIN PGP SIGNATURE----- Version: PGP 8.0 iQA/AwUBPlEFb6vEtUU05riwEQKFDQCghB6q64UaJ6F4MnEy+c2byNuER48AoNG6 H/nd9NIhbueKUNvr3KboLRZ8 =7+qY -----END PGP SIGNATURE-----
|