[c-nsp] site-to-site vpn, ipsec-gre, 2811/HSEC

Jens S Andersen jsa at aua.auc.dk
Wed Jan 7 02:22:38 EST 2009


Hi

Do a

show ip traffic 

If Frags: keeps incrementing try to reduce ip mtu and mss size.
Fragmented packets are reassembled by the cpu and then handed over to the
AIM for decryption.

I configure my gre/ipsec with ip mtu 1418 and adjust-mss 1300

-Jens


>I'm experimenting with a pair of cisco 2811 with the AIM-VPN/SSL-2
>running C2800NM-ADVIPSERVICESK9-M, 12.4(9)T7.  I've got them
>back-to-back, configured as shown below.

>With a single file transfer (tcp) through the boxes I am able to jam
>the processor at 99%/96%, which tells me I must be missing something.

>I checked and the "ip tcp adjust-mss 1360" is working, so it is not
>fragmentation that is the culprit.  I do get about 35Mbs throughput,
>but I'm bugged that the main cpu is jammed.  I did check "sh cry eng
>acc stat" and see that the HW module is being used, but I would have
>thought that the actual 2811 cpu would be only modestly busy.

>Am I missing anything here?

>Thanks,
>-mark

>---

> crypto isakmp policy 10
>  encr aes
>  authentication pre-share
>  group 5
>  lifetime 300
> !
> crypto isakmp key foo address 10.10.10.2 no-xauth
> !
> crypto ipsec transform-set GREVPN esp-aes esp-sha-hmac
> !
> crypto map GREVPN local-address FastEthernet0/0
> !
> ip access-list extended TUNNEL
>  permit gre host 10.10.10.1 host 10.10.10.2
> !
> crypto map GREVPN 20 ipsec-isakmp
>  set peer 10.10.10.2
>  set transform-set GREVPN
>  match address TUNNEL
> !
> interface Tunnel0
>  ip address 192.0.2.1 255.255.255.252
>  ip mtu 1476
>  ip tcp adjust-mss 1360
>  tunnel source FastEthernet0/0
>  tunnel destination 10.10.10.2
> !
> interface FastEthernet0/0
>  description x-conn to other 2811
>  ip address 10.10.10.1 255.255.255.252
>  crypto map GREVPN
>  crypto ipsec fragmentation before-encryption
> !
> interface FastEthernet0/1
>  ip address <test1 network, test2 is on other 2811>
> !
> ip route <test2 network> 192.0.2.2

>---

> 2811-expt-TWO#sh cry engine acc stat

> Device:   AIM-VPN/SSL-2
> Location: AIM Slot: 0
> Virtual Private Network (VPN) Module in slot : 0
>	 Statistics for Hardware VPN Module since the last clear
>	  of counters 42 seconds ago
>	  126270 packets in                      126270 packets out
>       127941213 bytes in                     124977694 bytes out
>	    3006 paks/sec in                       3006 paks/sec out
>	   23865 Kbits/sec in                     23312 Kbits/sec out
>	   42555 packets decrypted                83715 packets encrypted
>	 5854456 bytes before decrypt         119123238 bytes encrypted
>	 2790517 bytes decrypted              125150696 bytes after encrypt
>	       0 packets decompressed                 0 packets compressed
>	       0 bytes before decomp                  0 bytes before comp
>	       0 bytes after decomp                   0 bytes after comp
>	       0 packets bypass decompr               0 packets bypass compres
>	       0 bytes bypass decompres               0 bytes bypass compressi
>	       0 packets not decompress               0 packets not compressed
>	       0 bytes not decompressed               0 bytes not compressed
>	   1.0:1 compression ratio                1.0:1 overall
>	       4 commands out                         4 commands acknowledged
>	 Last 5 minutes:
>	   53276 packets in                       53276 packets out
>	    1268 paks/sec in                       1268 paks/sec out
>	10792372 bits/sec in                   10542446 bits/sec out
>	 1178581 bytes decrypted               50240550 bytes encrypted
>	  235716 Kbits/sec decrypted           10048110 Kbits/sec encrypted
>	   1.0:1 compression ratio                1.0:1 overall

> Errors:
>    ppq full errors         :        0   ppq rx errors           :        0
>    cmdq full errors        :        0   cmdq rx errors          :        0
>    ppq down errors         :        0   cmdq down errors        :        0
>    no buffer               :        0   replay errors           :        0
>    dest overflow           :        0   authentication errors   :        0
>    Other error             :        0   Raw Input Underrun      :        0
>    IPSEC Unsupported Option:        0   IPV4 Header Length      :        0
>    ESP Pad Length          :        0   IPSEC Decompression     :        0
>    AH ESP seq mismatch     :        0   AH Header Length        :        0
>    AH ICV Incorrect        :        0   IPCOMP CPI Mismatch     :        0
>    IPSEC ESP Modulo        :        0   Unexpected IPV6 Extensio:        0
>    Unexpected Protocol     :        0   Dest Buf overflow       :        0
>    IPSEC Pkt is fragment   :        0   IPSEC Pkt src count     :        0
>    Invalid IP Version      :        0   Unwrappable             :        0
>    SSL Output overrun      :        0   SSL Decompress failure  :        0
>    SSL BAD Decomp History  :        0   SSL Version Mismatch    :        0
>    SSL Input overrun       :        0   SSL Conn Modulo         :        0
>    SSL Input Underrun      :        0   SSL Connection closed   :        0
>    SSL Unrecognised content:        0   SSL record header length:        0
>    PPTP Duplicate packet   :        0   PPTP Exceed max missed p:        0
>    RNG self test fail      :        0   DF Bit set              :        0
>    Hash Miscompare         :        0   Unwrappable object      :        0
>    Missing attribute       :        0   Invalid attrribute value:        0
>    Bad Attribute           :        0   Verification Fail       :        0
>    Decrypt Failure         :        0   Invalid Packet          :        0
>    Invalid Key             :        0   Input Overrun           :        0
>    Input Underrun          :        0   Output buffer overrun   :        0
>    Bad handle value        :        0   Invalid parameter       :        0
>    Bad function code       :        0   Out of handles          :        0
>    Access denied           :        0   Out of memory           :        0
>    NR overflow             :        0   pkts dropped            :        0

> Warnings:
>    sessions_expired        :        0   packets_fragmented      :        0
>	    general:                :        0

> HSP details:
>    hsp_operations          :    35231   hsp_sessions            :        3
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Jens S Andersen                 Email:  jsa at adm.aau.dk
Aalborg University              Telf:   9940 9464
Selma Lagerlöfs Vej 300, 4.1.03 Fax:    9940 7593
9220 Aalborg
Denmark


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