46 Fabric OS FCIP Administrator’s Guide
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IPSec implementation over FCIP
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IPsec uses some terms that you should be familiar with before beginning your configuration. These
are standard terms, but are included here for your convenience.
The following limitations apply to using IPsec:
• IPv6, NAT, and AH are not supported.
• You can only create a single secure tunnel on a port; you cannot create a nonsecure tunnel on
the same port as a secure tunnel.
• IPsec-specific statistics are not supported.
• To change the configuration of a secure tunnel, you must delete the tunnel and recreate it.
• Jumbo frames are not supported for IPsec.
• There is no RAS message support for IPsec.
• Only a single route is supported on an interface with a secure tunnel.
• IPsec can only be configured on IPv4 based tunnels. Secure tunnels cannot be created on a
Brocade 7500 Extension Switch or FR4-18i blade if any IPv6 addresses are defined on either
ge0 or ge1.
TABLE 9 IPsec terminology
Term Definition
AES Advanced Encryption Standard. FIPS 197 endorses the Rijndael encryption algorithm as the
approved AES for use by US Government organizations and others to protect sensitive
information. It replaces DES as the encryption standard.
AES-XCBC Cipher Block Chaining. A key-dependent one-way hash function (MAC) used with AES in
conjunction with the Cipher-Block-Chaining mode of operation, suitable for securing messages
of varying lengths, such as IP datagrams.
AH Authentication Header - like ESP, AH provides data integrity, data source authentication, and
protection against replay attacks but does not provide confidentiality.
DES Data Encryption Standard is the older encryption algorithm that uses a 56-bit key to encrypt
blocks of 64-bit plain text. Because of the relatively shorter key length, it is not a secured
algorithm and no longer approved for Federal use.
3DES Triple DES is a more secure variant of DES. It uses three different 56-bit keys to encrypt blocks
of 64-bit plain text. The algorithm is FIPS-approved for use by Federal agencies.
ESP Encapsulating Security Payload is the IPsec protocol that provides confidentiality, data integrity
and data source authentication of IP packets, and protection against replay attacks.
IKE Internet Key Exchange is defined in RFC 2407, RFC 2408 and RFC 2409. IKEv2 is defined in
RFC 4306. IKE uses a Diffie-Hellman key exchange to set up a shared session secret, from
which cryptographic keys are derived and communicating parties are authenticated. The IKE
protocol creates a security association (SA) for both parties.
MD5 Message Digest 5, like SHA-1, is a popular one-way hash function used for authentication and
data integrity.
SHA Secure Hash Algorithm, like MD5, is a popular one-way hash function used for authentication
and data integrity.
MAC Message Authentication Code is a key-dependent, one-way hash function used for generating
and verifying authentication data.
HMAC A stronger MAC because it is a keyed hash inside a keyed hash.
SA Security Association is the collection of security parameters and authenticated keys that are
negotiated between IPsec peers.
