Cisco 897 Throughput

[morabusa]

Hello all,

I am having issues with a Cisco 897 Router connected directly to a provider ONT. We have a 600Mbps link but it seems like the router is just able to reach 200-250Mbps as much. I am trying to find in the router data sheet if I can find anything regarding this but without success. 

Router: C897VAG-LTE-GA-K9

IOS: c800-universalk9-mz.SPA.154-3.M3.bin

License Information for 'c800'
License Level: advipservices Type: Permanent
Next reboot license Level: advipservices

The link is connected in the interface Gigabitethernet8 and the router configuration includes NAT, GRE and IPSEC but we are just using the NAT for surfing on Internet.

Plus I have seen that input and overrun errors every time run a speed test:

RO897TRG#show interfaces gigabitEthernet 8
GigabitEthernet8 is up, line protocol is up
Hardware is PQ3_TSEC, address is 
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation 802.1Q Virtual LAN, Vlan ID 1., loopback not set
Keepalive set (10 sec)
Full Duplex, 1Gbps, media type is RJ45
output flow-control is unsupported, input flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 1111000 bits/sec, 129 packets/sec
5 minute output rate 149000 bits/sec, 91 packets/sec
9746965 packets input, 9191090485 bytes, 0 no buffer
Received 103 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
603 input errors, 0 CRC, 0 frame, 603 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
7244833 packets output, 1857642718 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out

Thank you very much for the help and Best Regards.

[mlund]

Hi

I found this. It will provide You with more information.

http://www.anticisco.ru/pubs/ISR_G2_Perfomance.pdf

/Mikael

[morabusa]

Hi Mlund,

Thank you for the information. So, according to this document, the 890 series recommended WAN link is just 15 Mbps, right?. Even for a link connected to a GigabitEthernet interface?

Thank you very much.

Best Regards.

[mlund]

Yes, that is the recomendation. But it all depends on the packet size mix and what services that is used, se for example table 6. That test shows a throughput of 75Mbps

[v.snijder]

Is this serious? Why would Cisco put Gigabitethernet ports (WAN & LAN) on a router that is not even capable of Fastethernet speed internally? 75 Mbps vs 1000 Mbps is a factor 13 too low for the standard.

[Joseph W. Doherty]

Why?

Only Cisco could say but as a couple of guesses, one possible reason it's easier to just manufacture one interface for all your devices.  Another possible reason, so that the interface can actually send/receive a frame at gig speed (although the device can not sustain the rate for a series of packets).

[v.snijder]

Very shocked to learn this. About the 897...

How about the C1100 series? Are these capable of handling Gigabit speed internet? As fiberoptic 1000 mbit subscriptions are quite available nowadays.

Even the flimsiest "$20 plastic boxes" you get for free from the provider can handle those throughputs with ease.

[Georg Pauwen]

Hello,

I think the 897 maxes out at about 500Mbps because that is all the CPU can handle. The upside is, and I am not pushing any product here, that no router has nearly the features that IOS provides. The question is of course, do you need these features, or is speed of the utmost importance...

[Joseph W. Doherty]

"I think the 897 maxes out at about 500Mbps because that is all the CPU can handle."

According to Cisco's performance documentation, the 890 series is a 100 Kpps device (for 64 byte Ethernet packets) that top outs at 1.4 Gbps in RFC 2544 testing.  However, that bandwidth forwarding rate is for 1500 byte packets (aggregate) with no features enabled.  I.e. very unlikely to see this level of performance in "real world".

Cisco also notes the 890 can provide 45 Mbps performance @75% CPU for IMIX traffic with ACLs, NAT and QoS.  Their recommendation to limit to WAN circuits of 15 Mbps (i.e. to 30 Mbps, assuming duplex) seems very conservative, but Cisco, I believe, doesn't want customers to, surprisingly, run out of CPU.

[Georg Pauwen]

I don't know if there was an evolution in these devices, a while ago I had an 897 installed, and could not get more than 500Mbps. Not sure which model version it was...

No ACLs or QoS, just NAT overload...

[Joseph W. Doherty]

I believe (?) each 8#x model, within a series, e.g. the 86x, 88x or 89x, has the same performance rating.  If so, impressive you were able to hit 500 Mbps on your 897.