Hi, On Sun, Sep 10, 2017 at 02:25:04PM +0300, Saku Ytti wrote:
On 10 September 2017 at 13:56, Thomas Bellman <bellman@nsc.liu.se> wrote:
An alternative is to just have link-local addresses on your point-to- point links. At least on your internal links where you run your IGP. On external links, where you run eBGP or static routes, it's probably more trouble than it is worth, though, since link-local addresses can change if you replace the hardware, requiring a config change on the other end. (Also, I'm not sure all BGP implementations support using link-local addresses.)
all BGP implementations I'm aware of do that (support LLAs), BUT at least Cisco's doesn't support using the same LLAs in multiple BGP sessions (e.g. on PE-CE links) which in turn ruins the potential benefits in many environments, see https://ripe72.ripe.net/presentations/122-ERNW_RIPE72_IPv6wg_RFC7404.pdf https://blog.apnic.net/2016/05/31/beauty-ipv6-link-local-addressing-not/
This is solvable problem. Vendors support 'bgp listen' or 'bgp allow' to accept BGP session from specific CIDR range. Similarly you could allow IPv6 on interface, with SADDR anywhere in link-local. Your own end link-local stability you could guarantee by manually configuring MAC address, instead of using BIA. I.e. customers would experience stable DADDR, but we wouldn't care about customer's SADDR.
However I don't think market would generally appreciate the implications linklocal brings to traceroute, where least bad option would be just to originate hop-limit exceeded from loop0, with no visibility on actual interface.
some might be willing to accept that, as a trade-off for other benefits operations-wise. best Enno -- Enno Rey ERNW GmbH - Carl-Bosch-Str. 4 - 69115 Heidelberg - www.ernw.de Tel. +49 6221 480390 - Fax 6221 419008 - Cell +49 173 6745902 Handelsregister Mannheim: HRB 337135 Geschaeftsfuehrer: Matthias Luft, Enno Rey ======================================================= Blog: www.insinuator.net || Conference: www.troopers.de Twitter: @Enno_Insinuator =======================================================