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Example 1 with BgpOrigin

use of org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.BgpOrigin in project bgpcep by opendaylight.

the class AbstractBestPathSelector method isExistingPathBetter.

/**
 * Chooses best route according to BGP best path selection.
 *
 * @param state attributes of the new route
 * @return true if the existing path is better, false if the new path is better
 */
protected boolean isExistingPathBetter(@Nonnull final BestPathState state) {
    /*
         * 2. prefer path with higher LOCAL_PREF
         *
         * FIXME: for eBGP cases (when the LOCAL_PREF is missing), we should assign a policy-based preference
         *        before we ever get here.
         */
    if (this.bestState.getLocalPref() == null && state.getLocalPref() != null) {
        return true;
    }
    if (this.bestState.getLocalPref() != null && state.getLocalPref() == null) {
        return false;
    }
    if (state.getLocalPref() != null && state.getLocalPref() > this.bestState.getLocalPref()) {
        return false;
    }
    if (state.getLocalPref() != null && state.getLocalPref() < this.bestState.getLocalPref()) {
        return true;
    }
    // 4. prefer the path with the shortest AS_PATH.
    if (this.bestState.getAsPathLength() != state.getAsPathLength()) {
        return this.bestState.getAsPathLength() < state.getAsPathLength();
    }
    // - IGP is lower than Exterior Gateway Protocol (EGP), and EGP is lower than INCOMPLETE
    if (!this.bestState.getOrigin().equals(state.getOrigin())) {
        final BgpOrigin bo = this.bestState.getOrigin();
        final BgpOrigin no = state.getOrigin();
        // This trick relies on the order in which the values are declared in the model.
        return no.ordinal() > bo.ordinal();
    }
    // FIXME: we should be able to cache the best AS
    final Long bestAs = this.bestState.getPeerAs();
    final Long newAs = state.getPeerAs();
    /*
         * Checks 6 and 7 are mutually-exclusive, as MEDs are comparable
         * only when the routes originated from the same AS. On the other
         * hand, when they are from the same AS, they are in the same iBGP/eBGP
         * relationship.
         *
         */
    if (bestAs.equals(newAs)) {
        // 6. prefer the path with the lowest multi-exit discriminator (MED)
        if (this.bestState.getMultiExitDisc() != null || state.getMultiExitDisc() != null) {
            final Long bmed = this.bestState.getMultiExitDisc();
            final Long nmed = state.getMultiExitDisc();
            return nmed > bmed;
        }
    } else {
        /*
             * 7. prefer eBGP over iBGP paths
             *
             * EBGP is peering between two different AS, whereas IBGP is between same AS (Autonomous System),
             * so we just compare the AS numbers to our AS.
             *
             * FIXME: we should know this information from the peer directly.
             */
        if (this.ourAs != bestAs && this.ourAs == newAs) {
            return true;
        }
    }
    /*
         * 10. Prefer the route that comes from the BGP router with the lowest router ID.
         *
         * This is normally guaranteed by the iteration order of our caller, which runs selection
         * in the order of increasing router ID, but RFC-4456 Route Reflection throws a wrench into that.
         *
         * With RFC-5004, this gets a bit easier, because it completely eliminates step f) and later :-)
         *
         * RFC-5004 states that this algorithm should end here and select existing path over new path in the
         * best path selection process. Benefits are listed in the RFC: @see http://tools.ietf.org/html/rfc500
         * - This algorithm SHOULD NOT be applied when either path is from a BGP Confederation peer.
         *  - not applicable, we don't deal with confederation peers
         * - The algorithm SHOULD NOT be applied when both paths are from peers with an identical BGP identifier
         *   (i.e., there exist parallel BGP sessions between two BGP speakers).
         *  - not applicable, BUG-2631 prevents parallel sessions to be created.
         */
    return true;
}
Also used : BgpOrigin(org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.BgpOrigin)

Example 2 with BgpOrigin

use of org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.BgpOrigin in project bgpcep by opendaylight.

the class OriginAttributeParser method parseAttribute.

@Override
public void parseAttribute(final ByteBuf buffer, final AttributesBuilder builder) throws BGPDocumentedException {
    final byte rawOrigin = buffer.readByte();
    final BgpOrigin borigin = BgpOrigin.forValue(UnsignedBytes.toInt(rawOrigin));
    if (borigin == null) {
        throw new BGPDocumentedException("Unknown Origin type.", BGPError.ORIGIN_ATTR_NOT_VALID, new byte[] { (byte) 0x01, (byte) 0x01, rawOrigin });
    }
    switch(borigin) {
        case Egp:
            builder.setOrigin(EGP);
            return;
        case Igp:
            builder.setOrigin(IGP);
            return;
        case Incomplete:
            builder.setOrigin(INC);
            return;
        default:
            return;
    }
}
Also used : BGPDocumentedException(org.opendaylight.protocol.bgp.parser.BGPDocumentedException) BgpOrigin(org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.BgpOrigin)

Aggregations

BgpOrigin (org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.BgpOrigin)2 BGPDocumentedException (org.opendaylight.protocol.bgp.parser.BGPDocumentedException)1