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netzwerghh
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CCR2216-1G-12XS-2XQ L3-Offload with multiple BGP full table (IPv4 and IPv6)

Thu May 19, 2022 10:34 am

We plan to replace our CCR2004 which are currently running as peering-router with BGP full table with CCR2216 due to constant packet loss when combined routed traffic exceeds 300 to 400 MBit.

Every router get's at least 2x the full v4 and v6 table (from our bird route reflectors). Those facing upstream also get another full table. And those facing IXPs have a lot of peering sessions getting between 2 and 150.000 routes each.

Internal backbone is held together with OSPF (Loopbacks and all transfer networks. Internal and to upstream).

So we have a lot of routes active. We would like to use the L3-Offloading feature of the CCR2216 but https://help.mikrotik.com/docs/display/ ... Offloading says there are 60K-120K routes supported for L3 offloading. What will happen when there are more routes than that? The above links states for CRS-models that those routes are simply ignored. Does that mean packets to those destinations will be dropped? Does this also apply to the CCR2216? In the above link there is no such information for the CCR2216. And what is the correct way to make such a setup? Will those routes learned from BGP automatically get offloaded when offloading is activated in switch chip and for the interfaces? How about when you have configured VLAN-interfaces for some ports? Our upstreams and IXPs give us more than one service per physical link. Each service in its own vlan.

I hope someone can give me some information about that. Before I try everything in our testlab. Just to rule out some things :-)
 
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Re: CCR2216-1G-12XS-2XQ L3-Offload with multiple BGP full table (IPv4 and IPv6)

Fri May 20, 2022 10:45 pm

The above links states for CRS-models that those routes are simply ignored.

Actual statement is that excess routes will be ignored by switch chip .. meaning that CPU will perform routing.
 
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netzwerghh
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Re: CCR2216-1G-12XS-2XQ L3-Offload with multiple BGP full table (IPv4 and IPv6)

Sat May 21, 2022 12:11 am

Thanks for the reply. Has anybody actually tried and tested this? I'm waiting for my testlab at the moment and will try it for myself. But I would like to know of others who already have experience.
 
rpingar
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Re: CCR2216-1G-12XS-2XQ L3-Offload with multiple BGP full table (IPv4 and IPv6)

Thu Jul 14, 2022 9:31 am

i am working about it but still get strange behavior when enabling l3hwoffload on chip and port and on some routes.
 
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chechito
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Re: CCR2216-1G-12XS-2XQ L3-Offload with multiple BGP full table (IPv4 and IPv6)

Thu Jul 14, 2022 4:18 pm

Layer 3 Hardware Offloading page has been updated recently

https://help.mikrotik.com/docs/display/ ... iceSupport
1 Since the total amount of routes that can be offloaded is limited, prefixes with higher netmask are preferred to be forwarded by hardware (e.g., /32, /30, /29, etc.), any other prefixes that do not fit in the HW table will be processed by the CPU.

at today in ipv4 full table is approx 900k routes and almost 60% of them have the highest netmask /24 that is 540k routes, prioritizing them help but still is necessary to select which of them to offload or not, fortunately there is a way

https://help.mikrotik.com/docs/display/ ... gHWOffload
By default, all the routes are participating to be hardware candidate routes. To further fine-tune which traffic to offload, there is an option for each route to disable/enable suppress-hw-offload.
...
Routing Filters
For dynamic routing protocols like OSFP and BGP, it is possible to suppress HW offloading using routing filters. For example, to suppress HW offloading on all OSFP instance routes, use "suppress-hw-offload yes" property

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